Drilling fluids containing an alkali metal formate

ABSTRACT

A drilling fluid or mud is described wherein the drilling fluid contains at least one alkali metal formate or monovalent carboxylic acid salt. The drilling fluid preferably further contains at least one emulsifier or surfactant and at least one hydrocarbon-based fluid. The drilling fluids of the present invention can contain other conventional ingredients. The present invention permits drilling fluids to be essentially solids free due to the use of the alkali metal formate.

[0001] This application claims the benefit under 35 U.S.C. §119(e) of prior U.S. Provisional Patent Application No. 60/268,520 filed Feb. 14, 2001, which is incorporated in its entirety by reference herein.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to the drilling industry and more particularly relates to drilling fluids used in drilling, such as the drilling of a well for the recovery of hydrocarbons or other materials.

[0003] In drilling operations, such as the drilling that occurs in oil field operations, drilling fluids are designed/formulated to serve several functions. These functions include acting as a lubricant to the drill bit to reduce wear and friction during drilling and also to seal the formation surface by forming a filter cake. Currently, in the industry, both oil-based muds (OBMs) and water based muds (WBMs) are typically used. More commonly, synthetic based muds (SBMs) are also used in drilling operations. In the drilling fluid, agents for lubrication are present as well as weighting materials in order to achieve a density that typically produces a pressure greater than the surrounding pressure in the well bore. Furthermore, the drilling fluid will also contain a sealing or fluid loss agent, such as calcium carbonate for pore bridging especially polysaccharides and other polymers, in order to form the filter cake on the formation surface of the well bore. In addition, when the drilling fluids are used during drilling, the drilling fluid will also contain drilling fines, such as shale and sandstone fines. During the drilling operations and afterwards, the filter cake seals the formation surface of the well bore so that the well bore can be completely formed without any leakage from the formation surface into the well bore and/or without any leakage of the drilling fluids into the formation surface. While the filter cake is beneficial for these reasons, once the drilling is completed, and the recovery of hydrocarbons is the next step, the filter cake can act as a severe impediment to the recovery of hydrocarbons. For instance, the filter cake can prevent the recovery of hydrocarbons from the formation surfaces which have been blocked or sealed by the filter cake. Furthermore, when injectors are used to retain reservoir pressures, the injection of sea water, for instance, can be significantly reduced due to the filter cake preventing the sea water from entering the formation and hence restricting the flow of water into the reservoir. Accordingly, the industry prefers to remove the filter cake from the well bore in order to optimize productivity. If the filter cake is not removed, the filter cake can block the pores that are part of the formation surface of the well bore which will interfere with the recovery of hydrocarbons. In many drilling operations, the drilling fluid can contain up to 5% by weight of a pore bridging material such as calcium carbonate. Calcium carbonate (CaCO3) is typically a blend of particle sizes with a particle size distribution designed to optimize the bridging of the pores found in the formation. The pore size distribution of the formation is determined from its permeability, preferably by direct porosity and permeability measurements of core plugs extracted from the reservoir.

[0004] Once drilling operations have been completed, the well is prepared for the completion operations whereby the mud used for drilling is often displaced by a completion fluid. Completion fluids are typically water based clear fluids and are formulated to the same density as the mud used to drill the well in order to retain the hydraulic pressure on the well bore. There are numerous methods of completing a well, amongst which are open hole completions and gravel packed screened systems. The clear fluids are typically halide based brines such as calcium bromide, calcium chloride, and zinc bromide; or organic based brines such as the formate based fluids.

[0005] In drilling an oil or gas well, the use of hydrocarbon-based drilling fluids are greatly preferred because of the inherent advantages of having an external phase fluid in contact with the formation. However, one severe disadvantage to a hydrocarbon-based drilling fluid is that weighting materials, such as barite, calcium carbonate, or hematite must be added to increase the density of the fluid. These weighting-material solids are capable of inducing formation damage to producing formations.

[0006] Thus, there is a need to provide hydrocarbon-based drilling fluids that are preferably solids free or have low solids in the contents in the drilling fluid in order to avoid the above-mentioned disadvantages.

SUMMARY OF THE PRESENT INVENTION

[0007] A feature of the present invention is to provide drilling fluids which are solids free or contain low amounts of solids in the drilling fluids.

[0008] Another feature of the present invention is to provide drilling fluids which are a hydrocarbon-water emulsion which are suitable for use as drilling fluids.

[0009] A further feature of the present invention is to provide drilling fluids which can have a variety of different densities in order to be useful in a variety of drilling situations depending on drilling depth and/or other variables.

[0010] Another feature of the present invention is to provide a more environmentally friendly drilling fluid that can be primarily aqueous based.

[0011] Additional features and advantages of the present invention will be set forth in part in the description that follows, and in part will be apparent from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention will be realized and attained by means of the elements and combinations particularly pointed out in the description and appended claims.

[0012] To achieve these and other advantages, and in accordance with the purposes of the present invention, as embodied and broadly described herein, the present invention relates to a drilling fluid which contains at least one alkali metal formate and preferably at least one surfactant. Additional alkali metal formates, wetting agents, hydrocarbons, solid weighting materials, sealing or fluid loss agents, filtration control agents, and/or polymers to further control viscosity and/or other conventional additives such as organoclays and the like can also be optionally present for purposes of the present invention.

[0013] The present invention further relates to a method to drill a well comprising drilling of a well in the presence of the above-mentioned drilling fluid of the present invention.

[0014] The present invention further relates to a method to minimize or eliminate solids in a drilling fluid by substituting at least a portion of the solids weighting material with at least one alkali metal formate and preferably at least one surfactant.

[0015] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide a further explanation of the present invention, as claimed.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0016] The present invention relates to drilling fluids for use in drilling operations. For instance, the drilling fluid can be used in the drilling of a well for hydrocarbon recovery such as oil and/or gas. The drilling fluids of the present invention can also be used in other drilling operations where drilling fluids are used.

[0017] The drilling fluid of the present invention contains at least one alkali metal formate or monovalent carboxylic acid salt and preferably at least one surfactant or emulsifier. The drilling fluid of the present invention can contain an emulsion of an aqueous-based solution with a hydrocarbon-based fluid for purposes of forming the drilling fluid wherein the drilling fluid contains at least one alkali metal formate and preferably at least one surfactant along with at least one hydrocarbon-based fluid.

[0018] Preferably, the drilling fluid contains cesium formate as the alkali metal formate. More preferably, the drilling fluid contains two or more alkali metal formates, wherein preferably one of the alkali metal formates is cesium formate. A preferred combination of formates includes, but is not limited to, cesium formate with potassium formate. Other combinations of alkali metal formates can be used, such as sodium formate and potassium formate or sodium formate and cesium formate. Essentially, any combination of one or more monovalent carboxylic salts can be used for purposes of the drilling fluids of the present invention.

[0019] The alkali metal formates are commercially available. For instance, the cesium formate can be obtained from Cabot Corporation. The cesium formate can be made, for instance, by following the description as set forth in International Published Patent Application No. WO 96/31435, incorporated in its entirety by reference herein. The cesium formate that is present in the drilling fluid, preferably as a soluble salt, as stated above, can be present in any concentration and the cesium formate solution is a liquid at room temperature. Therefore, the concentration of the cesium formate in the drilling fluid can be from about 1% to about 100% by weight, and more preferably is present in an amount of from about 40% to about 95% by weight, and even more preferably is present in the drilling fluid at a range of from about 55% to about 85% by weight or is present in the drilling fluid at a range of from about 70% to about 85% by weight based on the weight of the drilling fluid. Besides the optional ingredients and preferably the surfactant and/or hydrocarbon fluid, the remainder of the drilling fluid can be water or other aqueous solutions. Conventional ingredients used in drilling fluids can also be used with the drilling fluid of the present invention.

[0020] Other alkali metal formates that can be used in the present invention are potassium formate and sodium formate which are commercially available. These alkali metal formates can also be prepared in a similar fashion as the cesium formate solution described above, and are also frequently obtained as by-products from ester hydrolysis.

[0021] Preferably, with respect to the drilling fluid of the present invention, at least 35% by volume of the fluid in the drilling fluid is an aqueous-based solution containing at least one alkali metal formate. More preferably, at least 50% by volume of the fluids present in the drilling fluid is an aqueous-based solution containing at least one alkali metal formate and even more preferably at least 75% by volume of the fluids present in the drilling fluid of the present invention is an aqueous-based solution containing at least one alkali metal formate. Most preferably, at least 90% by volume of the fluids present in the drilling fluid of the present invention is an aqueous-based solution containing at least one alkali metal formate. In another embodiment, at least 95% or more by volume of the fluids of the present invention contain an aqueous-based solution containing at least one alkali metal formate. In one embodiment, all of the fluids present are an aqueous-based solution containing at least one alkali metal formate wherein essentially no hydrocarbon, or oil is present in the drilling fluid. Since the alkali formate is preferably dissolved in the aqueous solution, the drilling fluid can be solids free since the alkali formate preferably acts as a lubricant and a weighting material.

[0022] When a hydrocarbon fluid or synthetic mud fluid is present in the drilling fluids of the present invention, conventional hydrocarbon fluids or synthetic mud fluids can be used in the drilling fluids of the present invention. Examples include, but are not limited to, diesel oil such as diesel oil number 2, crude oil, synthetic oils (such as paraffin oils, olefin oils, vegetable oils, and the like), as well as other conventional hydrocarbon fluids. Combinations of various hydrocarbon fluids or synthetic mud fluids can be used for purposes of the present invention. If a hydrocarbon or synthetic mud fluid is present in the drilling fluid of the present invention, various ratios of the hydrocarbon fluid to the aqueous-based solution described above can be used, such as ratios of 65% by volume hydrocarbon fluid: 35% aqueous based solution to 1% by volume hydrocarbon fluid: 99% by volume aqueous based solution.

[0023] When a hydrocarbon fluid is present with the aqueous-based solution containing at least one alkali metal formate, at least one emulsifier or surfactant is preferably present in order to produce an emulsion of the ingredients. Essentially any emulsifier(s) or surfactant(s) capable of forming an emulsion between the hydrocarbon fluid and the aqueous based solution can be used for purposes of the present invention. Examples include, but are not limited to, a dimer trimer acid such as Witco DTA 350, imidazoline, tall oil (stearic acid), Integrity Synvert IV, Integrity Synvert TWA, and the like. Any amount of surfactant or emulsifier can be used to form the emulsion such as from about 1 to about 30 pounds per barrel, wherein a barrel is about 42 gallons.

[0024] Other optional ingredients that can be present in the drilling fluids of the present invention include a filtration control agent or pore bridging materials such as Gilsonite and the like. These filtration control agents can be used in conventional amounts.

[0025] Other ingredients that can be present in the drilling fluids of the present invention include solid weighting materials such as barite, hematite, and/or calcium carbonate. These solid weighting materials can be used if desired. The amount of solid weighting material, which is optional, can be from about 0.5 pound per barrel to about 500 pounds per barrel.

[0026] Another optional ingredient in the drilling fluids of the present invention is a wetting agent which can be helpful in emulsifying the alkali metal formate fluids with the hydrocarbon-based external fluids. An example of a suitable wetting agent is Integrity Synvert TWA. Conventional amounts can be used in combination with the emulsifiers described above in order to achieve desired emulsions of the formate fluids with the hydrocarbon-base external fluids.

[0027] Other ingredients that can optionally be present include, but are not limited to, other drilling fluid products such as polymer(s) to add to viscosity, hydrophilic clays, organophilic clays, fluid loss control additives, amine-treated clays, clays treated such that they provide viscosity in non-aqueous fluids, and the like. These other optional ingredients can be used in conventional amounts known to those skilled in the art.

[0028] The alkali metal formate that is present as part of the aqueous-based solution can be not fully saturated in the aqueous-based solution so as to permit any remaining water-soluble components to preferably solubilize in the solution along with the alkali metal formate. Thus, the alkali metal formate that is present in the aqueous-based solution can be present in an amount of less than 80% by weight, based on the aqueous-based solution basis, and more preferably is from about 60% to about 80% by weight.

[0029] The important advantage of the present invention is the ability for the density of the drilling fluid to be adjusted to any desired density. This can especially be done with the introduction of a combination of alkali metal formates, such as potassium formate with cesium formate. As an example, an aqueous-based portion of the drilling fluid can contain cesium formate which can range from about 1.8 to about 2.4 s.g. This density range can be adjusted with the introduction of potassium formate. For instance, when 0 to 100% by weight of potassium formate is included in the aqueous-based portion of the drilling fluid, the density of the overall aqueous-based portion of the drilling fluid can range from about 1.2 to about 2.4. Thus, the density of the drilling fluid can essentially be “dialed-in” to meet the density needed for the drilling fluid to be used in the drilling of the well bore at the appropriate depths. For lower density ranges, sodium formate can be added to the potassium formate, hence, “dialing-in” lower density drilling fluids.

[0030] Thus, the drilling fluids of the present invention make it possible to achieve a variety of different densities and to minimize or completely eliminate the solid weighting material that is present in conventional drilling fluids.

[0031] The drilling fluids of the present invention can be introduced into the well bore by any conventional technique such as, but not limited to, being pumped into the drill pipe. Further, the drilling fluids can be recovered using conventional techniques.

[0032] The drilling fluids of the present invention can be prepared by mixing all of the components together. When an emulsion is prepared, typically, the components will be mixed together such as by shearing in order to ensure a dispersion that is preferably uniform with respect to the components.

[0033] For example, a typical paraffinic hydrocarbon oil such as ESCAID 110, having a density of 0.803 s.g. (6.7 ppg) and a cesium formate solution having a density of 2.2 s.g. (18.36 ppg) when combined in a ratio of 1:1 and by addition of an emulsifier or a series of emulsifiers admixed by shearing, the fluids together can produce an emulsion or microemulsion that has a cesium formate invert phase or (internal phase) and an oil external phase. The density of the combined mixture of this example is 1.51 s.g. (12.6 ppg).

[0034] For purposes of the present invention, when a hydrocarbon-based external fluid is used with at least one formate fluid as described above, the formate fluids can be partially or totally emulsified into the hydrocarbon-based fluid. Or, in the alternative, when a majority of the drilling fluid is a formate fluid, the hydrocarbon-based fluid, if present, can be partially or totally emulsified into the formate fluid.

[0035] Optionally, the drilling fluids of the present invention can also contain at least one acid. Preferably, the acid is an acid containing at least one carboxylic group and more preferably is formic acid or an acid derivative thereof. Other examples of acids that can be used include, but are not limited to, acetic acid, ascorbic acid, citric acid, tartaric acid, phthalic acid, glycolic acid, and combinations thereof. The acid can be present in various amounts such as from about 1% or less to 25 weight % or more based on the weight of the drilling fluid. The presence of the acid has the capability of adjusting the pH of the drilling fluid as well as providing other benefits to the drilling fluid. When an acid is present, for instance, the alkali metal formate fluid, such as cesium formate, can be present in any molar amount, but is preferably present in an amount of about 3 M. Similarly, the acid, when present, can be present in any molar amount, and is preferably present in an amount of from about 2.2 M to about 15 M. The pH of the drilling fluid can be any pH.

[0036] The present invention will be further clarified by the following examples, which are intended to be purely exemplary of the present invention.

EXAMPLES

[0037] Various drilling fluid formulations were prepared and tested to determine the ability of the drilling fluids to serve as suitable fluids for drilling.

[0038] In the Examples, cesium formate was used and as can be seen in the results summarized in the various tables, a drilling fluid was made that had low or zero solids content and had the capability to “dial-in” various densities using a combination of components described herein.

[0039] In the examples, a barrel is generally 42 gallons of liquid. IA-35 is a synthetic oil from Integrity Industries. Integrity Synvis is a viscosifier. Witco DTA 350 is a wetting agent. Baroid Baracarb 50 is calcium carbonate. Initial ES (volts) is electrical stability at the temperature shown below the values. Initial properties refers to apparent viscosity using a Fann 35 viscometer. SA refers to static-aged ES testing and 250 refers to testing at 250° F. for 16 hours. “Silv” refers to a Silverson mixer.

[0040] The tests in the Tables were conducted in accordance with Recommended Practice Standard Procedure for Field Testing oil-based drilling fluids, API, 13B-2 (2^(nd) Ed., Dec. 1, 1991), and Recommended Practice Standard Procedure API Recommended Procedure 13-I (5^(th) Ed., Jun. 1, 1995), incorporated in their entirety by reference herein. Cesium formate, IA - 35 (50/50 mixture, 2.3 s.g. CsF) 2.3 sg csf Mixing Procedure: 1. Measure out IA - 35 1A. Add Synvis, mix 5 minutes 2. Add CsF, mix 10 min. 3. Add Emulsifier Synvert, mix 10 minutes 3A. Add calcium carbonate, mix 10 minutes 4. Run initial ES, viscosities at 120° F. 5. Put 10 ml sample in a vial, SA for 24 hrs at 75° F., measure volumes 6. Hot-roll for 16 hours at 150° F. 7. Remix, run rheology, ES, API, HTHP at 150° F. 8. Put vials in oven and static-age at 150° F. for 24 hrs, measure volumes 9. If 150° F. HTHP is good, run at 250° F. 41.6/58.4 oil/csf ratio Sample # 337 338 339 IA - 35, 98.26 98.26 93.26 grams Cesium 445 (2.366) 445 (2.366) 445 (2.366) Formate, grams Integrity 25 25 20 Emulsifier, lb/bbl Integrity 0.5 1 0.5 Synvis, lb/bbl Witco — — — DTA 350, lb/bbl Baroid 50 50 50 Baracarb 50, lb/bbl Initial ES, 103 129 167 166 114 151 volts Hot-rolled 114 102 148 140 139 138 16 hrs, ES Initial Properties 120° F. 150° F. 120° F. 150° F. 120° F. 150° F. 600 rpm 162 116 186 118 164 115 300 rpm 93 65 114 67 96 66 200 rpm 67 47 83 49 70 48 100 rpm 40 27 49 29 41 28   6 rpm 8 7 9 6 7 6   3 rpm 6 5 7 5 5 5 Plastic 69 51 72 51 68 49 Viscosity, cP Yield Pt, lb/ 24 14 42 16 28 17 100 ft{circumflex over ( )}2 Gels, 10 sec/ 6/7 6/6 6/7 5/6 5/6 5/5 10 min. Settling in no no no no no no thermocup HR 16 hrs at 150° F. 600 rpm 161 113 187 123 162 114 300 rpm 93 64 116 70 97 66 200 rpm 68 46 86 52 72 48 100 rpm 39 27 52 30 473 28   6 rpm 8 6 10 6 7 6   3 rpm 6 5 8 5 5 4 Plastic 68 49 71 53 65 48 Viscosity, cP Yield Pt, 25 15 45 17 32 18 lb/100 ft{circumflex over ( )}2 Gels, 10 6/6 5/6 7/9 5/6 6/6 5/5 sec/10 min. API filt, 1.0 0.2 0.4 ml total API filt, — — — ml oil API filt, 1.0 0.2 0.4 ml emulsion API filt, — — — ml brine HTHP at 0.2 150° F., ml HTHP at 11.4 250° F., ml 250° F. oil 0.0 250° F. 6.8 emulsion 250° F. brine 4.6 Comments NOTE: 1. Sample 337 and 338 looked grainy with 15 lb/bbl Synvert V. Concentration was increased to 25 lb/bbl. After hot-rolling at 150° F., #337 and #338 still appear grainy. 2. Mud weight of 339 is 14.7 lb/gal (CsF in 337-339 is 2.366 s.g) 41.6/58.4 oil/csf ratio Sample # 340 347 348 IA - 35, grams 93.26 88.26 88.26 Cesium 455 (2.366) 445 (2.3) 445 (2.3) Formate, grams Integrity 20 25 25 Emulsifier, lb/bbl Integrity 1 — — Synvis, lb/bbl Witco — 0.5 1 DTA 350, lb/bbl Baroid 50 50 50 Baracarb 50, lb/bbl Initial ES, 117 128 212 192 205 243 volts Hot-rolled 122 118 148 145 252 247 16 hrs, ES Initial Properties 120° F. 150° F. 120° F. 150° F. 120° F. 150° F. 600 rpm 183 126 177 132 182 132 300 rpm 109 73 106 78 111 80 200 rpm 80 53 77 57 83 61 100 rpm 47 31 46 347 52 38   6 rpm 8 6 8 7 10 8   3 rpm 6 5 6 5 7 6 Plastic 74 53 71 54 71 52 Viscosity, cP Yield Pt, lb/ 35 20 35 24 40 28 100 ft{circumflex over ( )}2 Gels, 10 sec/ 6/7 5/5 6/6 6/6 8/8 6/7 10 min. Settling in no no no no no no thermocup HR 16 hrs at 150° F. 600 rpm 184 129 179 140 184 144 300 rpm 111 75 109 84 113 88 200 rpm 82 55 80 62 85 66 100 rpm 49 32 48 37 52 41   6 rpm 8 6 8 7 10 9   3 rpm 6 5 6 5 8 7 Plastic 73 56 70 56 71 56 Viscosity, cP Yield Pt, 38 28 39 32 42 32 lb/100 ft{circumflex over ( )}2 Gels, 10 6/7 5/6 6/6 5/5 8/8 7/9 sec/10 min. API filt, 0.3 3.5 6.2 ml total API filt, — — — ml oil API filt, 0.3 3.5 6.2 ml emulsion API filt, — — — ml brine HTHP at 0.2 19.4 (0.8 brine) 150° F., ml HTHP at 4.4 250° F. ml 250° F. oil 0.0 250° F. 3.2 emulsion 250° F. 1.2 brine Comments NOTE 1. Mud weight of 339 is 14.7 lb/gal (CsF in 340 is 2.366 s.g) 2. Mud weight of 347 is 14.6 lb/gal (CsF in 347-348 is 2.30 s.g) 41.6/58.4 oil/csf ratio Sample # 341 342 343 344 345 346 IA - 35, 88.26 88.26 98.26 98.26 93.26 93.26 grams Cesium 445 445 445 445 445 445 Formate, grams Integrity 25 25 15 15 20 20 Emulsifier, lb/bbl Integrity 0.5 1 — — — — Synvis, lb/bbl Witco — — 0.5 1 0.5 1 DTA 350, lb/bbl Baroid 50 50 50 50 50 50 Baracarb 50, lb/bbl

[0041] Cesium Formate, Escaid 110 (50/50 mixture) Mixing Procedure: 1. Measure out Escaid 110, add Organoclay, mix 10 minutes 2. Add emulsifier(s), mix 5 minutes, add Gilsonite, mix 10 minutes 3. Add CsF, mix 10 min on HB, add CaCO3, mix 10 min on HB 4. Run initial ES, viscosities at 120 F. 5. Put 10 ml sample in vial, SA for 24 hrs at 75 F., measure volume 6. Hot Roll for 16 hrs. at 150 F. 7. Remix, run rheology es, HPHT @ 250 F. 8. Put vial in oven SA 24 hrs @ 150 F. Sample # E-1 E-2 E-3 E-4 Integrity Synvert IV, lb/bbl 10 15 10 10 Dimer-Trimer acid, lb/bbl 0 0 0 1 Integrity Synvert TWA, lb/bbl 0 0 0 6 Organoclay, lb/bbl 0 0 4 4 Gilsonite, lb/bbl 0 0 5 5 CaCo3, lb/bbl 0 0 50 50 ES @ 120 F. 225 289 170 175 Hot-rolled 16 hrs, ES @ 120 F. 395 440 365 350 Initial Properties 600 rpm @ 120 F. 28 30 85 92 300 rpm @ 120 F. 15 16 40 50 200 rpm @ 120 F. 10 11 31 41 100 rpm @ 120 F. 5 6 15 25 6 rpm @ 120 F. 0 1 3 6 3 rpm @ 120 F. 0 0 1 5 Plastic Viscosity, cP 13 14 45 42 Yield Point, lb/100 ftsq 2 2 5 8 Gels, 10 sec/10 min 0/0 0/1 1/4 5/8 HR 16 hrs @ 150 F. 600 rpm @ 120 F. 31 33 96 110 300 rpm @ 120 F. 16 18 49 62 200 rpm @ 120 F. 10 12 35 53 100 rpm @ 120 F. 5 6 20 40 6 rpm @ 120 F. 0 2 4 10 3 rpm @ 120 F. 0 1 2 6 Plastic Viscosity, cP 15 15 47 48 Yield Point, lb/100 ftsq 1 3 4 14 Gels, 10 sec/10 min. 0/0 1/1 3/4 7/9 HPHT @ 250 F., ml 30 26 8 6 Water in filtrate, ml 4 3 0 0 24 hrs @ 75 F. Free Oil % 10 8 5 3 Emulsion % 90 92 95 97 Free Brine % 0 0 0 0

[0042] Cesium Formate, IA-35 (75/25 mixture) Mixing Procedure: 1. Measure out IA-35, add Organoclay, mix 10 minutes 2. Add emulsifier(s), mix 5 minutes, add Gilsonite, mix 10 minutes 3. Add CsF, mix 10 min on HB, add CaCO3, mix 10 min on HB 4. Run initial ES, viscosities at 120 F. 5. Put 10 ml sample in vial, SA for 24 hrs at 75 F. measure volume 6. Hot Roll for 16 hrs. at 250 F. 7. Remix, run rheology es, HPHT @ 150 F. 8. Put vials in oven SA 24 hrs @ 150 F. Sample # 1 2 3 4 5 Integrity Synvert IV, lb/bbl 10 15 10 10 15 Dimer-Trimer acid, lb/bbl 0 0 0 1 1 Integrity Synvert TWA, lb/bbl 0 0 0 6 6 Organoclay, lb/bbl 0 0 4 4 4 Gilsonite, lb/bbl 0 0 5 5 5 CaCo3, lb/bbl 0 0 50 50 50 ES @ 120 F. 226 250 270 175 225 Hot-rolled 16 hrs, ES @ 120 F. 185 200 Initial Properties 600 rpm @ 120 F. 251 265 t t t 300 rpm @ 120 F. 169 172 o o o 200 rpm @ 120 F. 135 133 o o o 100 rpm @ 120 F. 92 184   6 rpm @ 120 F. 26 13 t t t   3 rpm @ 120 F. 20 8 h h h i i i Plastic Viscosity, cP 82 93 c c c Yield Point, lb/100 ftsq 87 79 k k k Gels, 10 sec/10 min 24/28 8/12 HR 16 hrs @ 150 F. 600 rpm @ 120 F. 276 259 300 rpm @ 120 F. 175 166 200 rpm @ 120 F. 140 101 100 rpm @ 120 F. 99 22   6 rpm @ 120 F. 29 14   3 rpm @ 120 F. 22 8 Plastic Viscosity, cP 101 93 Yield Point, lb/100 ftsq 74 73 Gels, 10 sec/10 min. 22/23 8/12 HPHT @ 250 F., ml 23 16 Water in filtrate, ml 8 4 24 hrs @ 75 F. Free Oil % 1 0 0 Emulsion % 99 100 100 Free Brine % 0 0 0 24 hrs @ 150 F. Free oil % 2 2 0 Emulsion % 98 98 100 Free Brine % 0 0 0

[0043] Cesium Formate, IA-35 (50/50 mixture) Mixing Procedure: 1. Measure out IA-35, add Organoclay, mix 10 minutes 2. Add emulsifier(s), mix 5 minutes, add Gilsonite, mix 10 minutes 3. Add CsF, mix 10 min on HB, add CaCO3, mix 10 min on HB 4. Run initial ES, viscosities at 120 F. 5. Put 10 ml sample in vial, SA for 24 hrs at 75 F., measure volume 6. Hot Roll for 16 hrs. at 150 F. 7. Remix, run rheology es, HPHT @ 250 F. 8. Put vials in oven SA 24 hrs @ 150 F. Sample # 1 2 3 4 5 Integrity Synvert IV, lb/bbl 10 15 10 10 15 Dimer-Trimer acid, lb/bbl 0 0 0 1 1 Integrity Synvert TWA, lb/bbl 0 0 0 6 6 Organoclay, lb/bbl 0 0 4 4 4 Gilsonite, lb/bbl 0 0 5 5 5 CaCo3, lb/bbl 0 0 50 50 50 ES @ 120 F. 226 255 241 150 231 Hot-rolled 16 hrs, ES @ 120 F. 425 475 427 320 444 Initial Properties 600 rpm @ 120 F. 39 42 162 181 155 300 rpm @ 120 F. 20 22 93 131 92 200 rpm @ 120 F. 14 15 66 110 67 100 rpm @ 120 F. 7 8 36 81 39   6 rpm @ 120 F. 0 1 3 33 6   3 rpm @ 120 F. 0 0 2 28 4 Plastic Viscosity, cP 19 20 69 50 63 Yield Point, lb/100 ftsq 1 2 24 81 29 Gels, 10 sec/10 min 0/0 0/2 3/7 29/32 7/7 HR 16 hrs @ 150 F. 600 rpm @ 120 F. 51 55 169 195 188 300 rpm @ 120 F. 27 29 101 145 114 200 rpm @ 120 F. 14 14 75 113 86 100 rpm @ 120 F. 9 10 43 87 51   6 rpm @ 120 F. 1 1 4 37 8   3 rpm @ 120 F. 0 1 2 30 5 Plastic Viscosity, cP 24 26 68 50 74 Yield Point, lb/100 ftsq 3 3 33 95 40 Gels, 10 sec/10 min. 0/0 0/1 3/3 33/35 5/6 HPHT @ 250 F., ml 28 22 15 14 6 Water in filtrate, ml 4 3 2 2 0 24 hrs @ 75 F. Free Oil % 5 10 4 3 2 Emulsion % 95 90 96 97 98 Free Brine % 0 0 0 0 0 24 hrs @ 150 F. Free oil % 18 15 10 0 Emulsion % 92 85 90 94 Free Brine % 0 0 0 0

[0044] Cesium formate, Escaid 110 (50/50 mixture) 175 ml Escaid 110 (0.803 sg) - (140.5 grams) 175 ml Cesium Formate (2.2 sg) - (385 grams) Mixing Procedure: 1. Measure out Escaid 110, add Geltone II, mix 10 minutes 2. Add emulsifiers (Below in bold), mix 5 minutes, add Barablock, mix 10 minutes 3. Add CsF, mix 10 min. on HB, add Lo-Wate, mix 10 min. on HB 4. Run initial ES, viscosities at 120° F. 5. Put 10 ml sample in a vial, SA for 24 hrs at 75° F., measure volumes 6. Hot-roll for 16 hours at 150° F. 7. Remix, run rheology, ES, API, HTHP at 150° F. 8. Put vials in oven and static-age at 150° F. for 24 hrs, measure volumes 9. If 150° F. HTHP is good, run at 250° F. Sample # 225 226 227 228 229 230 Integrity 7 7 7 7 7 7 Synvert II (Lot# 991512), lb/bbl Witco DTA 350 1 1 1 1 1 1 (dimer-trimer), lb/bbl Integrity 2 4 6 2 4 6 Synvert TWA (Jan. 24, 2000, D116), lb/bbl Baroid Geltone — — — 4 4 4 II, lb/bbl Baroid — — — — — — Barablock 400, lb/bbl M-I Lo-Wate, 50 50 50 50 50 50 lb/bbl Initial ES, 107 194 247 127 123 128 volts Hot-rolled 16 426 450 290 150 185 170 hrs, ES Initial Properties 600 rpm at 80 67 80 99 74 87 75° F. 300 rpm 58 48 60 75 52 60 200 rpm 49 40 51 64 43 48 100 rpm 37 31 39 49 31 35   6 rpm 13 10 13 18 12 13   3 rpm 10 5 4 15 10 11 Plastic 22 19 20 24 22 27 Viscosity, cP Yield Pt, 36 29 40 51 30 33 lb/100 ft{circumflex over ( )}2 Gels, 10 sec/10 min. 11/7 5/7 7/3 15/15 10/10 10/11 HR 16 hrs at 150° F. 600 rpm at 71 89 95 94 75 70 120° F. 300 rpm 53 69 74 68 52 48 200 rpm 44 59 63 56 43 39 100 rpm 34 45 49 42 31 28   6 rpm 10 12 12 17 12 10   3 rpm 4 5 4 13 10 8 Plastic 18 20 21 26 23 22 Viscosity, cP Yield Pt, 35 49 53 42 29 26 lb/100 ft{circumflex over ( )}2 Gels, 7/4 9/4 10/4 12/13 10/11 9/9 10 sec/10 min. API filtrate, 0.8 1.1 1.1 1.6 0.9 0.6 ml API Filtrate, 0 0 0 0 0 0 oil API Filtrate, 0 0 0 0 0 0 brine HTHP at 8.8 3.0 5.0 3.5 1.6 0.8 150° F., ml Water in 6.0 2.5 2.5 1.5 0.4 0.0 filtrate? HTHP at 24.0 18.0 12.0 8.2 4.2 2.5 250° F., ml Water in 12.0 9.0 3.1 2.6 1.7 0.6 filtrate? 24 hrs at 75° F. Total fluid 34 35 34 35 36 33 heighth free oil 6 3 2 1 1 2 heighth emusion 28 32 32 34 35 31 heighth free brine 0 0 0 0 0 0 heighth free oil, % 18% 9% 6% 3% 3% 6% emusion, % 82% 91% 94% 97% 97% 94% free brine, % 0% 0% 0% 0% 0% 0% 24 hrs at 150° F. Total fluid 34 36 35 35 37 32 heighth free oil 8 8 6 3 3 4 heighth emusion 26 28 29 32 34 28 heighth free brine 0 0 0 0 0 0 heighth free oil, % 24% 22% 17% 9% 8% 13% emusion, % 76% 78% 83% 91% 92% 88% free brine, % 0% 0% 0% 0% 0% 0% Difference (72 hrs/24 hrs at 150° F.) free oil, % 6% 14% 11% 6% 5% 6% emusion, % −6% −14% −11% −6% −5% −6% free brine, % 0% 0% 0% 0% 0% 0% Sample # 231 232 233 234 235 236 Integrity 7 7 7 7 7 7 Synvert II (Lot# 991512), lb/bbl Witco DTA 350 1 1 1 1 1 1 (dimer-trimer), lb/bbl Integrity 2 4 6 2 4 6 Synvert TWA (Jan. 24, 2000, D116), lb/bbl Baroid Geltone — — — 4 4 4 II, lb/bbl Baroid 5 5 5 5 5 5 Barablock 400, lb/bbl M-I Lo-Wate, 50 50 50 50 50 50 lb/bbl Initial ES, 139 263 249 105 133 161 volts Hot-rolled 402 314 307 144 196 245 16 hrs, ES Initial Properties 600 rpm at 81 90 85 86 81 84 75° F. 300 rpm 63 69 65 62 57 60 200 rpm 52 59 55 50 47 49 100 rpm 40 46 43 37 34 37   6 rpm 17 14 14 12 14 14   3 rpm 12 5 5 10 12 12 Plastic 18 21 20 24 24 24 Viscosity, cP Yield Pt, 45 48 45 38 33 36 lb/100 ft{circumflex over ( )}2 Gels, 10 17/15 10/5 11/6 10/11 12/13 12/12 sec/10 min. HR 16 hrs at 150° F. 600 rpm at 111 118 122 63 90 110 120° F. 300 rpm 84 92 96 43 62 76 200 rpm 71 78 83 35 50 62 100 rpm 53 61 65 25 37 45   6 rpm 17 18 21 9 13 16   3 rpm 7 7 7 7 11 14 Plastic 27 26 26 20 28 34 Viscosity, cP Yield Pt, 57 66 70 23 34 42 lb/100 ft{circumflex over ( )}2 Gels, 10 13/5 12/6 13/5 7/8 10/11 13/14 sec/10 min. API filtrate, 1.2 1.2 0.3 0.2 0.2 0.0 ml API Filtrate, 0 0 0 0 0 0 oil API Filtrate, 0 0 0 0 0 0 brine HTHP at 2.6 2.0 1.4 2.0 trace trace 150° F., ml Water in 0.0 0.0 0.0 0.0 0.0 0.0 filtrate? HTHP at 9.0 8.0 6.0 7.0 5.0 4.0 250° F., ml Water in 0.0 0.0 0.0 0.0 0.0 0.0 filtrate? 24 hrs at 75° F. Total fluid 35 35 35 34 34 34 heighth free oil 3 2 3 2 1 1 heighth emusion 32 33 32 32 33 33 heighth free brine 0 0 0 0 0 0 heighth free oil, % 9% 6% 9% 6% 3% 3% emusion, % 91% 94% 91% 94% 97% 97% free brine, % 0% 0% 0% 0% 0% 0% 24 hrs at 150° F. Total fluid 35 36 35 34 35 35 heighth free oil 7 6 6 6 4 3 heighth emusion 28 30 29 28 31 32 heighth free brine 0 0 0 0 0 0 heighth free oil, % 20% 17% 17% 18% 11% 9% emusion, % 80% 83% 83% 82% 89% 91% free brine, % 0% 0% 0% 0% 0% 0% Difference (72 hrs/24 hrs at 150° F.) free oil, % 11% 11% 9% 12% 8% 6% emusion, % −11% −11% −9% −12% −8% −6% free brine, % 6% 0% 0% 0% 0% 0%

[0045] Mixing Order: 1. Measure out IA 35 base oil 2. Add Synvert IV 3. Add cesium formate 4. Mix on HB, Silverson to 135° F. Sample # 1 2 3 4 5 IA-35, % 90 75 50 25 10 Synvert IV, 20 20 20 20 20 lb/bbl 2.2 s.g. Cs 10 25 50 75 90 Formate, % Initial Rheologies Mud weight, 7.81 9.4 11.94 14.47 17.18 lb/gal 600 rpm at 7 13 42 >300 too 120° F. 300 rpm 4 7 21 274 thick 200 rpm 3 5 14 218 to 100 rpm 2 3 7 149 measure   6 rpm 0.2 0.5 1 38   3 rpm 0.2 0.5 0.5 28 PV 3 6 21 — — YP 1 1 0 — — Gels .5/.5 1/1 1/1 28/32 — ES 373 310 362 328 133 Vials 16 hrs at 75° F. Total Heighth 32 32 32 31 Oil 18 1 0 0 Emulsion 14 31 32 31 Formate Samples H.R. for 16 hours at 150° F. 600 rpm at 6 13 45 >300 too 120° F. 300 rpm 3 7 23 273 thick 200 rpm 2 4 16 222 to 100 rpm 1 2 8 158 measure   6 rpm 0 0 2 49   3 rpm 0 0 2 40 PV 3 6 22 — — YP 0 1 1 — — Gels 1/1 0/0 2/2 38/42 — ES 1069 211 232 271 115 Vials 7 hrs at 150° F. Total Heighth 32 32 32 32 Oil 22 3 1 0 Emulsion 10 29 31 32 Formate Vials 64 hrs at 200° F. Total Heighth 105 103 100 100 105 Oil 89 66 40 0 0 Emulsion 8 12 60 100 105 Formate 8 25 0 0 0 Vials 64 hrs at 250° F. Total Heighth 103 100 100 100 110 Oil 95 70 30 32 0 Emulsion 8 7 65 60 110 Formate 0 23 5 8 0 Vials 64 hrs at 300° F. Total Heighth 102 105 102 102 104 Oil 92 70 42 32* 19* Emulsion 10 10 10 Formate 0 25 50 70 85

[0046] Integrity Synvert IV Sample 1 gallon can Test Procedure 1. Mix sample 2. Place aliquots of sample in large test tubes 3. Static-age samples for 24 hours at 200, 250, and 300 F., 300 psi N2 4. Static-age samples for 72 hours at 200, 250, and 300 F., 300 psi N2 5. Measure total heighth, oil, emulsion, and brine 200° F. 250° F. 300° F. 24 hour tests Total heighth, mm 100 99 99 Free Oil, mm 9 16 30 Emulsion, mm 84 73 46 Free Brine, mm 7 10 23 % Oil 9.0% 16.2% 30.3% % Emulsion 84.0% 73.7% 46.5% % Brine 7.0% 10.1% 23.2% 72 hour tests Total heighth, mm 96 101 97 Free Oil, mm 5 10 30 Emulsion, mm 81 71 22 Free Brine, mm 10 20 45 % Oil 5.2% 9.9% 30.9% % Emulsion 84.4% 70.3% 22.7% % Brine 10.4% 19.8% 46.4% Note: the 24 hr 300° F., and the 72 hour 200 and 250° F. fluids appeared to have two phases in the emulsion portion. One phase is more distinctly oil and the second phase is more distinctly emulsion. Sample of 50/50 mix from Integrity (one gallon can) 600 rpm at 75° F. 90 300 rpm 49 200 rpm 34 100 rpm 18   6 rpm 2   3 rpm 1 PV 41 YP 8 Gels 2/2 ES 457 Integrity Turpene-Formate Sample 3 days 7 days Vials 3 and 7 days at 200° F. Total Heighth 50 52 Oil 20 15 Emulsion 0 0 Formate 30 37 Vials 3 and 7 days at 250° F. Total Heighth 54 51 Oil 17 15 Emulsion 0 0 Formate 37 36 Vials 3 and 7 days at 300° F. Total Heighth 51 50 Oil 15 15 Emulsion 0 0 Formate 36 35 Sample # SA 250 SA 250 SA 250 SA 250 Initial Silv. Initial Silv. 349 349.5 349.75 350 350.5 350.75 353 IA - 35, grams 94.26 94.26 94.26 94.26 94.26 94.26 89.26 Cesium Formate, 445 445 445 445 445 445 445 grams Integrity 20 20 20 20 20 20 25 Emulsifier, lb/bbl Integrity 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Synvis, lb/bbl Witco DTA — — — 0.5 0.5 0.5 — 350, lb/bbl Baroid — — — — — — — Barablock, lb/bbl M-I Lo Wate, 50 50 50 50 50 50 50 lb/bbl Initial 227 256 301 ES, volts Hot-rolled 109 209 339 16 hrs, ES Static-aged 113 154 ES, volts Initial Properties 120° F. 120° F. 120° F. 120° F. 120° F. 120° F. 120° F. 600 rpm 188 147 — 179 148 — 203 300 rpm 113 90 — 108 88 — 122 200 rpm 83 68 — 80 65 — 90 100 rpm 49 41 — 48 39 — 53   6 rpm 8 6 — 6 6 — 7   3 rpm 5 4 — 4 4 — 5 Plastic 75 57 — 71 60 — 81 Viscosity, cP Yield Pt, 38 33 — 37 28 — 41 lb/100 ft{circumflex over ( )}2 Gels, 10 5/6 5/6 — 4/5 4/6 — 6/6 sec/10 min. Settling in no no — no no — no thermocup Initial 253 266 295 ES, volts Hot-rolled 205 145 331 222 175 330 242 16 hrs, ES HR 16 hrs at 150° F. 150° F. 150° F. 150° F. 150° F. 150° F. 150° F. 150° F. 600 rpm 137 98 121 137 104 121 158 300 rpm 81 58 70 82 60 70 95 200 rpm 60 42 51 61 44 51 70 100 rpm 36 25 30 37 26 30 42   6 rpm 7 4 5 7 5 5 8   3 rpm 5 3 3 5 3 3 6 Plastic 56 40 51 55 44 51 63 Viscosity, cP Yield Pt, 25 18 19 27 16 19 32 lb/100 ft{circumflex over ( )}2 Gels, 10 6/6 3/3 3/4 5/5 3/4 3/4 6/6 sec/10 min. API filt, 0.7 — — 0.4 — — 0.3 ml total API filt, 0 — — 0 — — 0 ml oil API filt, 0.7 — — 0.4 — — 0.3 ml emulsion API filt, 0.0 — — 0.0 — — 0.0 ml brine HTHP at 3.2 — 1.6 8.8 — 2.0 4.8 250° F., ml 250° F. 2.4 — — 6 — — 3.6 oil 250° F. 0.8 — 1.6 2.8 — 2.0 1.2 emulsion 250° F. — — — — — — — brine Free Oil, % 22% 25% Sample # SA 250 SA 250 SA 250 SA 250 Initial Silv. Initial Silv. 353.5 353.75 354 354.5 354.75 IA - 35, grams 89.26 89.26 89.26 89.26 89.26 Cesium Formate, 445 445 445 445 445 grams Integrity 25 25 25 25 25 Emulsifier, lb/bbl Integrity 0.5 0.5 0.5 0.5 0.5 Synvis, lb/bbl Witco DTA 350, — — 0.5 0.5 0.5 lb/bbl Baroid — — — — — Barablock, lb/bbl M-I Lo Wate, 50 50 50 50 50 lb/bbl Initial ES, 384 volts Hot-rolled 16 306 hrs, ES Static-aged 150 240 ES, volts Initial Properties 120° F. 120° F. 120° F. 120° F. 120° F. 600 rpm 159 — 224 205 — 300 rpm 97 — 138 125 — 200 rpm 73 — 103 93 — 100 rpm 44 — 65 56 —   6 rpm 7 — 10 9 —   3 rpm 5 — 7 7 — Plastic 62 — 86 80 — Viscosity, cP Yield Pt, 35 — 52 45 — lb/100 ft{circumflex over ( )}2 Gels, 10 6/7 — 7/8 — sec/10 min. Settling in no — no no — thermocup Initial 387 ES, volts Hot-rolled 161 369 314 218 336 16 hrs, ES HR 16 hrs at 150° F. 150° F. 150° F. 150° F. 150° F. 150° F. 600 rpm 114 136 167 133 157 300 rpm 68 80 102 78 94 200 rpm 50 59 76 57 69 100 rpm 30 35 47 34 41   6 rpm 5 7 10 6 6   3 rpm 4 5 8 4 4 Plastic 46 56 65 55 63 Viscosity, cP Yield Pt, 22 24 37 23 31 lb/100 ft{circumflex over ( )}2 Gels, 10 4/5 5/6 8/8 5/5 5/5 sec/10 min. API filt, — — 1.8 — — ml total API filt, — — 0.1 — — ml oil API filt, — — 1.7 — — ml emulsion API filt, — — 0.0 — — ml brine HTHP at — 2.4 3.6 — 4.8 250° F., ml 250° F. oil — — 0.4 — 0.3 250° F. — 1.0 3.2 — 2.5 emulsion 250° F. — 1.4 — — 2.0 brine Free Oil, % 25% 25% Sample # 351 355 359 IA - 35, 94.26 89.26 84.26 grams Cesium 445 (2.3) 445 (2.3) 445 (2.3) Formate, grams Integrity 20 25 30 Emulsifier, lb/bbl Integrity 0.5 0.5 0.5 Synvis, lb/bbl Witco 0.5 0.5 0.5 DTA 350, lb/bbl Baroid 10 10 10 Barablock, lb/bbl M-I Lo Wate, 50 50 50 lb/bbl Initial ES, 301 300 357 365 440 492 volts Hot-rolled 308 348 328 325 368 389 16 hrs, ES Initial Properties 120° F. 150° F. 120° F. 150° F. 120° F. 150° F. 600 rpm 195 193 241 227 300+ 300+ 300 rpm 117 120 147 143 253 233 200 rpm 87 91 111 110 196 182 100 rpm 53 56 70 70 127 119   6 rpm 7 10 12 15 28 29   3 rpm 5 7 8 11 20 22 Plastic 78 73 94 84 — — Viscosity, cP Yield Pt, 39 47 53 59 — — lb/100 ft{circumflex over ( )}2 Gels, 10 5/6 8/9 8/10 11/14 19/22 22/26 sec/10 min. Settling in no no 1 2 9 10 thermocup HR 16 hrs at 150° F. 600 rpm 300+ 226 300+ 274 300+ 300+ 300 rpm 201 140 246 171 300+ 242 200 rpm 154 106 188 129 282 186 100 rpm 98 67 119 81 181 121   6 rpm 20 15 25 19 42 32   3 rpm 15 11 19 15 32 26 Plastic — 86 — 103 — — Viscosity, cP Yield Pt, — 54 — 68 — — lb/ 100 ft{circumflex over ( )}2 Gels, 10 14/19 11/12 18/22 14/15 32/33 25/27 sec/10 min. API filt, 0 0.0 0.0 ml total API filt, — 0.0 0.0 ml oil API filt, 0 0.0 0.0 ml emulsion API filt, — 0.0 0.0 ml brine HTHP at 150° F., ml HTHP at trace 1.2 trace 250° F., ml 250° F. 0.0 0.0 oil 250° F. 1.2 trace emulsion 250° F. 0.0 0.0 brine

[0047] Cesium formate, IA - 35 (42/58 mixture, 2.3 s.g. CsF) 2.3 sg csf Mixing Procedure: 1. Measure out IA - 35 2. Add Synvis, mix 5 minutes 3. Add CsF, mix 10 min. 4. Add Synvert 5, mix 10 minutes 5. Add DTA 350, mix on Silverson to 120° F. 6. Add calcium carbonate, mix 10 minutes on HB 7. Run initial ES, viscosities at 120° F. 8. Put 10 ml sample in a vial, SA for 24 hrs at 75° F., measure 9. Hot-roll for 16 hours at 150° F. 10. Remix, run rheology, ES, API, HTHP at 150° F. 11. Put vials in oven and static-age at 150° F. for 24 hrs, measure 12. If 150° F. HTHP is good, run at 250° F. Sample # 349 350 351 352 IA - 35, 94.26 94.26 94.26 94.26 grams Cesium 445 (2.3) 445 (2.3) 445 (2.3) 445 (2.3) Formate, grams Integrity 20 20 20 20 Emulsifier, lb/bbl Integrity 0.5 0.5 0.5 0.5 Synvis, lb/bbl Witco DTA — 0.5 0.5 1.0 350, lb/bbl Baroid — — 10 — Barablock, lb/bbl M-I Lo Wate, 50 50 50 50 lb/bbl Initial 227 253 256 266 301 300 283 365 ES, volts Hot-rolled 109 205 209 222 308 348 262 276 16 hrs, ES Initial Properties 120° F. 150° F. 120° F. 150° F. 120° F. 150° F. 120° F. 150° F. 600 rpm 188 138 179 134 195 193 179 146 300 rpm 113 81 108 80 117 120 112 92 200 rpm 83 59 80 59 87 91 84 70 100 rpm 49 35 48 35 53 56 53 43   6 rpm 8 6 6 5 7 10 7 6   3 rpm 5 5 4 4 5 7 4 4 Plastic 75 57 71 54 78 73 67 54 Viscosity, cP Yield Pt, 38 24 37 26 39 47 45 38 lb/100 ft{circumflex over ( )}2 Gels, 10 5/6 5/5 4/5 4/5 5/6 8/9 4/5 5/5 sec/10 min. Settling in no no no no no no no no thermocup HR 16 hrs at 150° F. 600 rpm 187 137 196 137 300+ 226 189 143 300 rpm 114 81 120 82 201 140 119 90 200 rpm 85 60 90 61 154 106 91 69 100 rpm 52 36 56 37 98 67 60 44   6 rpm 9 7 9 7 20 15 12 9   3 rpm 7 5 7 5 15 11 8 6 Plastic 73 56 76 55 — 86 70 53 Viscosity, cP Yield Pt, 41 25 44 27 — 54 49 37 lb/100 ft{circumflex over ( )}2 Gels, 10 7/7 6/6 6/8 5/5 14/19 11/12 8/10 6/7 sec/10 min. API filt, 0.7 0.4 0 1.2 ml total API filt, — — — 0.1 ml oil API filt, 0.7 0.4 0 1.1 ml emulsion API filt, — — — — ml brine HTHP at — — 150° F., ml HTHP at 3.2 8.8 trace 3.6 250° F., ml 250° F. oil 2.4 6.0 2.8 250° F. 0.8 2.8 0.8 emulsion 250° F. 0.0 0.0 0.0 brine Comments 24 hrs at 75° F. Total fluid 38 38 38 38 heighth free oil 0 0 0 0 heighth emusion 38 38 38 38 heighth free brine 0 0 0 0 heighth free oil, % 0 0 0 0 emusion, % 100% 100% 100% 100% free brine, % 0 0 0 0 24 hrs at 150° F. Total fluid 38 38 38 38 heighth free oil 0 0 0 0 heighth emusion 38 38 38 38 heighth free brine 0 0 0 0 heighth free oil, % 0 0 0 0 emusion, % 100% 100% 100% 100% free brine, % 0 0 0 0 Sample # 355 356 357 358 IA - 35, grams 89.26 89.26 84.26 84.26 Cesium Formate, 445 (2.3) 445 (2.3) 445 (2.3) 445 (2.3) grams Integrity 25 25 30 30 Emulsifier, lb/bbl Integrity 0.5 0.5 0.5 0.5 Synvis, lb/bbl Witco DTA 0.5 1.0 — 0.5 350, lb/bbl Baroid 10 — — — Barablock, lb/bbl M-I Lo Wate, 50 50 50 50 lb/bbl Initial 357 365 329 311 335 316 344 321 ES, volts Hot-rolled 328 325 307 307 298 301 301 272 16 hrs, ES Initial Properties 120° F. 150° F. 120° F. 150° F. 120° F. 150° F. 120° F. 150° F. 600 rpm 241 227 196 154 235 182 245 190 300 rpm 147 143 121 95 147 110 150 116 200 rpm 111 110 92 72 108 82 113 86 100 rpm 70 70 59 46 67 51 70 53   6 rpm 12 15 11 10 13 11 13 11   3 rpm 8 11 8 7 10 8 9 8 Plastic 94 84 75 59 88 72 95 74 Viscosity, cP Yield Ft, 53 59 46 36 59 38 55 42 lb/100 ft{circumflex over ( )}2 Gels, 10 8/10 11/14 8/9 7/8 9/10 9/9 9/10 8/9 sec/10 min. Settling in 1 2 3 4 5 6 7 8 thermocup HR 16 hrs at 150° F. 600 rpm 300+ 274 201 153 229 174 245 185 300 rpm 246 171 124 94 140 106 151 112 200 rpm 188 129 95 71 105 79 114 84 100 rpm 119 81 60 49 65 49 70 52   6 rpm 25 19 12 10 13 12 14 11   3 rpm 19 15 9 8 10 9 10 8 Plastic — 103 77 59 89 68 94 73 Viscosity, cP Yield Pt, — 68 47 35 51 38 57 39 lb/100 ft{circumflex over ( )}2 Gels, 10 18/22 14/15 9/10 8/8 10/10 9/10 10/11 8/9 sec/10 min. API filt, 0.0 1.8 0.0 1.0 ml total API filt, 0.0 0.1 0.0 trace ml oil API filt, 0.0 1.7 0.0 1.0 ml emulsion API filt, 0.0 0.0 0.0 0.0 ml brine HTHP at 150° F., ml HTHP at 1.2 7.4 4.8 4.4 250° F., ml 250° F. oil 0.0 0.0 0.0 0.0 250° F. 1.2 7.4 4.8 4.4 emulsion 250° F. 0.0 0.0 0.0 0.0 brine Comments 24 hrs at 75° F. Total fluid 38 38 38 38 heighth free oil heighth 0 0 0 0 emusion heighth 38 38 38 38 free brine 0 0 0 0 heighth free oil, % 0 0 0 0 emusion, % 100% 100% 100% 100% free brine, % 0 0 0 0 24 hrs at 150° F. Total fluid 38 38 38 38 heighth free oil trace of oil trace of oil trace of oil trace of oil heighth emusion 38 38 38 38 heighth free brine 0 0 0 0 heighth free oil, % trace trace trace trace emusion, % 100% 100% 100% 100% free brine, % 0 0 0 0 Sample # 353 354 359 360 IA - 35, grams 89.26 89.26 84.26 84.26 Cesium Formate, 445 (2.3) 445 (2.3) 445 (2.3) 445 (2.3) grams Integrity 25 25 30 30 Emulsifier, lb/bbl Integrity 0.5 0.5 0.5 0.5 Synvis, lb/bbl Witco DTA — 0.5 0.5 1.0 350, lb/bbl Baroid — — 10 — Barablock, lb/bbl M-I Lo Wate, 50 50 50 50 lb/bbl Initial 301 295 384 387 440 492 457 481 ES, volts Hot-rolled 339 242 306 314 368 389 377 366 16 hrs, ES Initial Properties 120° F. 150° F. 120° F. 150° F. 120° F. 150° F. 120° F. 150° F. 600 rpm 203 155 224 171 300+ 300+ 261 219 300 rpm 122 92 138 104 253 233 167 142 200 rpm 90 68 103 77 196 182 129 109 100 rpm 53 41 65 47 127 119 84 70   6 rpm 7 7 10 8 28 29 14 12   3 rpm 5 5 7 7 20 22 9 8 Plastic 81 63 86 67 — — 94 77 Viscosity, cP Yield Pt, 41 29 52 37 — — 73 65 lb/100 ft{circumflex over ( )}2 Gels, 10 6/6 5/6 7/8 7/7 19/22 22/26 9/11 8/10 sec/10 min. Settling in no no no no 9 10 11 12 thermocup HR 16 hrs at 150° F. 600 rpm 212 158 225 167 300+ 300+ 262 192 300 rpm 131 95 140 102 300+ 242 168 123 200 rpm 97 70 105 76 282 186 131 95 100 rpm 60 42 66 47 181 121 86 64   6 rpm 11 8 13 10 42 32 20 14   3 rpm 8 6 10 8 32 26 15 11 Plastic 81 63 85 65 — — 94 69 Viscosity, cP Yield Pt, 50 32 55 37 — — 74 54 lb/100 ft{circumflex over ( )}2 Gels, 10 8/9 6/6 10/10 8/8 32/33 25/27 14/15 10/12 sec/10 min. API filt, 0.3 1.8 0.0 0.3 ml total API filt, — 0.1 0.0 trace ml oil API filt, 0.3 1.7 0.0 0.3 ml emulsion API filt, — — 0.0 0.0 ml brine HTHP at 150° F., ml HTHP at 4.8 3.6 trace 3.6 250° F., ml 250° F. oil 3.6 0.4 0.0 0.0 250° F. 1.2 3.2 trace 1.6 emulsion 250° F. 0.0 0.0 0.0 2.0 brine Comments 24 hrs at 75° F. Total fluid 38 38 38 38 heighth free oil 0 0 0 0 heighth emusion 38 38 38 38 heighth free brine 0 0 0 0 heighth free oil, % 0 0 0 0 emusion, % 100% 100% 100% 100% free brine, % 0 0 0 0 24 hrs at 150° F. Total fluid 38 38 38 38 heighth free oil 0 0 0 0 heighth emusion 38 38 38 38 heighth free brine 0 0 0 0 heighth free oil, % 0 0 0 0 emusion, % 100% 100% 100% 100% free brine, % 0 0 0 0 Sample # SA 250 SA 250 SA 250 SA 250 Initial Silv. Initial Silv. 349 349.5 349.75 350 350.5 350.75 351 352 IA - 35, grams 94.26 94.26 94.26 94.26 94.26 94.26 94.26 94.26 Cesium Formate, 445 445 445 445 445 445 445 445 grams Integrity 20 20 20 20 20 20 20 20 Emulsifier, lb/bbl Integrity 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Synvis, lb/bbl Witco DTA — — — 0.5 0.5 0.5 0.5 1.0 350, lb/bbl Baroid — — — — — — 10 — Barablock, lb/bbl M-I Lo Wate, 50 50 50 50 50 50 50 50 lb/bbl Initial 227 256 301 283 ES, volts Hot-rolled 109 209 308 262 16 hrs, ES Static-aged 113 154 ES, volts Initial Properties 120° F. 120° F. 120° F. 120° F. 120° F. 120° F. 120° F. 120° F. 600 rpm 188 147 — 179 148 — 195 179 300 rpm 113 90 — 108 88 — 117 112 200 rpm 83 68 — 80 65 — 87 84 100 rpm 49 41 — 48 39 — 53 53   6 rpm 8 6 — 6 6 — 7 7   3 rpm 5 4 — 4 4 — 5 4 Plastic 75 57 — 71 60 — 78 67 Viscosity, cP Yield Pt, 38 33 — 37 28 — 39 45 lb/100 ft{circumflex over ( )}2 Gels, 10 5/6 5/6 — 4/5 4/6 — 5/6 4/5 sec/10 min. Settling in no no — no no — no no thermocup HR 16 hrs at 150° F. 600 rpm 187 196 300+ 189 300 rpm 114 120 201 119 200 rpm 85 90 154 91 100 rpm 52 56 98 60   6 rpm 9 9 20 12   3 rpm 7 7 15 8 Plastic 73 76 — 70 Viscosity, cP Yield Pt, 41 44 — 49 lb/100 ft{circumflex over ( )}2 Gels, 10 7/7 6/8 14/19 8/10 sec/10 min. Comments Initial 253 266 300 365 ES, volts Hot-rolled 205 145 331 222 175 330 348 276 16 hrs, ES Initial Properties 150° F. 150° F. 150° F. 150° F. 600 rpm 138 134 193 146 300 rpm 81 80 120 92 200 rpm 59 59 91 70 100 rpm 35 35 56 43   6 rpm 6 5 10 6   3 rpm 5 4 7 4 Plastic 57 54 73 54 Viscosity, cP Yield Pt, 24 26 47 38 lb/100 ft{circumflex over ( )}2 Gels, 10 5/5 4/5 8/9 5/5 sec/10 min. Settling in no no no no thermocup SA 250 SA 250 SA 250 SA 250 Initial Silv. Initial Silv. HR 16 hrs at 150° F. 150° F. 150° F. 150° F. 150° F. 150° F. 150° F. 150° F. 150° F. 600 rpm 137 98 121 137 104 121 226 143 300 rpm 81 58 70 82 60 70 140 90 200 rpm 60 42 51 61 44 51 106 69 100 rpm 36 25 30 37 26 30 67 44   6 rpm 7 4 5 7 5 5 15 9   3 rpm 5 3 3 5 3 3 11 6 Free Oil, % 22% 25% Sample # SA 250 SA 250 SA 250 SA 250 Initial Silv. Initial Silv. 353 353.5 353.75 354 354.5 354.75 355 IA - 35, 89.26 89.26 89.26 89.26 89.26 89.26 89.26 grams Cesium 445 445 445 445 445 445 445 Formate, grams Integrity 25 25 25 25 25 25 25 Emulsifier, lb/bbl Integrity 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Synvis, lb/bbl Witco DTA — — — 0.5 0.5 0.5 0.5 350, lb/bbl Baroid — — — — — — 10 Barablock, lb/bbl M-I Lo Wate, 50 50 50 50 50 50 50 lb/bbl Initial 301 384 357 ES, volts Hot-rolled 339 306 328 16 hrs, ES Static-aged 150 240 ES, volts Initial Properties 120° F. 120° F. 120° F. 120° F. 120° F. 120° F. 120° F. 600 rpm 203 159 — 224 205 — 241 300 rpm 122 97 — 138 125 — 147 200 rpm 90 73 — 103 93 — 111 100 rpm 53 44 — 65 56 — 70   6 rpm 7 7 — 10 9 — 12   3 rpm 5 5 — 7 7 — 8 Plastic 81 62 — 86 80 — 94 Viscosity, cP Yield Pt, 41 35 — 52 45 — 53 lb/100 ft{circumflex over ( )}2 Gels, 10 6/6 6/7 — 7/8 — 8/10 sec/10 min. Settling in no no — no no — 1 thermocup HR 16 hrs at 150° F. 600 rpm 212 225 300+ 300 rpm 131 140 246 200 rpm 97 105 188 100 rpm 60 66 119   6 rpm 11 13 25   3 rpm 8 10 19 Plastic 81 85 — Viscosity, cP Yield Pt, 50 55 — lb/100 ft{circumflex over ( )}2 Gels, 10 8/9 10/10 18/22 sec/10 min. Comments Initial 295 387 365 ES, volts Hot-rolled 242 161 369 314 218 336 325 16 hrs, ES Initial Properties 150° F. 150° F. 150° F. 600 rpm 155 171 227 300 rpm 92 104 143 200 rpm 68 77 110 100 rpm 41 47 70   6 rpm 7 8 15   3 rpm 5 7 11 Plastic 63 67 84 Viscosity, cP Yield Pt, 29 37 59 lb/100 ft{circumflex over ( )}2 Gels, 10 5/6 7/7 11/14 sec/10 min. Settling in no no no thermocup SA 250 SA 250 SA 250 SA 250 Initial Silv. Initial Silv. HR 16 hrs at 150° F. 150° F. 150° F. 150° F. 150° F. 150° F. 150° F. 150° F. 600 rpm 158 114 136 167 133 157 274 300 rpm 95 68 80 102 78 94 171 200 rpm 70 50 59 76 57 69 129 100 rpm 42 30 35 47 34 41 81   6 rpm 8 5 7 10 6 6 19   3 rpm 6 4 5 8 4 4 15 Free Oil, % 25% 25% Sample # 356 357 358 359 360 IA - 35, grams 89.26 84.26 84.26 84.26 84.26 Cesium Formate, 445 445 445 445 445 grams Integrity 25 30 30 30 30 Emulsifier, lb/bbl Integrity 0.5 0.5 0.5 0.5 0.5 Synvis, lb/bbl Witco DTA 1.0 — 0.5 0.5 1.0 350, lb/bbl Baroid — — — 10 — Barablock, lb/bbl M-I Lo Wate, 50 50 50 50 50 lb/bbl Initial 329 335 344 440 457 ES, volts Hot-rolled 307 298 301 368 377 16 hrs, ES Static-aged ES, volts Initial Properties 120° F. 120° F. 120° F. 120° F. 120° F. 600 rpm 196 235 245 300+ 261 300 rpm 121 147 150 253 167 200 rpm 92 108 113 196 129 100 rpm 59 67 70 127 84   6 rpm 11 13 13 28 14   3 rpm 8 10 9 20 9 Plastic 75 88 95 — 94 Viscosity, cP Yield Pt, 46 59 55 — 73 lb/100 ft{circumflex over ( )}2 Gels, 10 8/9 9/10 9/10 19/22 9/11 sec/10 min. Settling in 3 5 7 9 11 thermocup HR 16 hrs at 150° F. 600 rpm 201 229 245 300+ 262 300 rpm 124 140 151 300+ 168 200 rpm 95 105 114 282 131 100 rpm 60 65 70 181 86   6 rpm 12 13 14 42 20   3 rpm 9 10 10 32 15 Plastic 77 89 94 — 94 Viscosity, cP Yield Pt, 47 51 57 — 74 lb/100 ft{circumflex over ( )}2 Gels, 10 9/10 10/10 10/11 32/33 14/15 sec/10 min. Comments Initial 311 316 321 492 481 ES, volts Hot-rolled 307 301 272 389 366 16 hrs, ES Initial Properties 150° F. 150° F. 150° F. 150° F. 150° F. 600 rpm 154 182 190 300+ 219 300 rpm 95 110 116 233 142 200 rpm 72 82 86 182 109 100 rpm 46 51 53 119 70   6 rpm 10 11 11 29 12   3 rpm 7 8 8 22 8 Plastic 59 72 74 — 77 Viscosity, cP Yield Pt, 36 38 42 — 65 lb/100 ft{circumflex over ( )}2 Gels, 10 7/8 9/9 8/9 22/26 8/10 sec/10 min. Settling in no no no no no thermocup HR 16 hrs at 150° F. 600 rpm 153 174 185 300+ 192 300 rpm 94 106 112 242 123 200 rpm 71 79 84 186 95 100 rpm 49 49 52 121 64   6 rpm 10 12 11 32 14   3 rpm 8 9 8 26 11 Free Oil, %

[0048] Cesium formate, IA - 35 (50/50 mixture, 2.3 s.g. CsF) Mixing Procedure: 2.3 sg csf 1. Measure out IA - 35 1A. Add Synvis, mix 5 minutes 2. Add CsF, mix 10 min. 3. Add Synvert 5, mix 10 minutes 3A. Add calcium carbonate, mix 10 minutes 4. Run initial ES, viscosities at 120° F. 5. Put 10 ml sample in a vial, SA for 24 hrs at 75° F., measure volumes 6. Hot-roll for 16 hours at 150° F. 7. Remix, run rheology, ES, API, HTHP at 150° F. 8. Put vials in oven and static-age at 150° F. for 24 hrs, measure volumes 9. If 150° F. HTHP is good, run at 250° F. 41.6/58.4 oil/csf ratio Sample # 337 338 339 340 IA - 35, grams 98.26 98.26 93.26 93.26 Cesium 445 445 445 445 Formate, (2.366) (2.366) (2.366) (2.366) grams Integrity 25 25 20 20 Emulsifier, lb/bbl Integrity 0.5 1 0.5 1 Synvis, lb/bbl Witco DTA — — — — 350, lb/bbl Baroid 50 50 50 50 Baracarb 50, lb/bbl Initial 103 129 167 166 114 151 117 128 ES, volts Hot-rolled 114 102 148 140 139 138 122 118 16 hrs, ES Initial Properties 120° F. 150° F. 120° F. 150° F. 120° F. 150° F. 120° F. 150° F. 600 rpm 162 116 186 118 164 115 183 126 300 rpm 93 65 114 67 96 66 109 73 200 rpm 67 47 83 49 70 48 80 53 100 rpm 40 27 49 29 41 28 47 31   6 rpm 8 7 9 6 7 6 8 6   3 rpm 6 5 7 5 5 5 6 5 Plastic 69 51 72 51 68 49 74 53 Viscosity, cP Yield Pt, 24 14 42 16 28 17 35 20 lb/100 ft{circumflex over ( )}2 Gels, 10 6/7 6/6 6/7 5/6 5/6 5/5 6/7 5/5 sec/10 min. Settling in no no no no no no no no thermocup HR 16 hrs at 150° F. 600 rpm 161 113 187 123 162 114 184 129 300 rpm 93 64 116 70 97 66 111 75 200 rpm 68 46 86 52 72 48 82 55 100 rpm 39 27 52 30 473 28 49 32   6 rpm 8 6 10 6 7 6 8 6   3 rpm 6 5 8 5 5 4 6 5 Plastic 68 49 71 53 65 48 73 56 Viscosity, cP Yield Pt, 25 15 45 17 32 18 38 28 lb/100 ft{circumflex over ( )}2 Gels, 10 6/6 5/6 7/9 5/6 6/6 5/5 6/7 5/6 sec/10 min. API filt, 1.0 0.2 0.4 0.3 ml total API filt, — — — — ml oil API filt, 1.0 0.2 0.4 0.3 ml emulsion API filt, — — — — ml brine HTHP at 0.2 0.2 150° F., ml HTHP at 11.4 4.4 250° F., ml 250° F. oil 0.0 0.0 250° F. 6.8 3.2 emulsion 250° F. 4.6 1.2 brine Comments 41.6/58.4 oil/csf ratio Sample # 347 348 341 342 343 344 345 346 IA - 35, 88.26 88.26 88.26 88.26 98.26 98.26 93.26 93.26 grams Cesium 445 445 445 445 445 445 445 445 Formate, grams (2.3) (2.3) Integrity 25 25 25 25 15 15 20 20 Emulsifier, lb/bbl Integrity — — 0.5 1 — — — — Synvis, lb/bbl Witco DTA 0.5 1 — — 0.5 1 0.5 1 350, lb/bbl Baroid 50 50 50 50 50 50 50 50 Baracarb 50, lb/bbl Initial 212 192 205 243 ES, volts Hot-rolled 148 145 252 247 16 hrs, ES Initial Properties 120° F. 150° F. 120° F. 150° F. 600 rpm 177 132 182 132 300 rpm 106 78 111 80 200 rpm 77 57 83 61 100 rpm 46 347 52 38   6 rpm 8 7 10 8   3 rpm 6 5 7 6 Plastic 71 54 71 52 Viscosity, cP Yield Pt, 35 24 40 28 lb/100 ft{circumflex over ( )}2 Gels, 10 6/6 6/6 8/8 6/7 sec/10 min. Settling in no no no no thermocup HR 16 hrs at 150° F. 600 rpm 179 140 184 144 300 rpm 109 84 113 88 200 rpm 80 62 85 66 100 rpm 48 37 52 41   6 rpm 8 7 10 9   3 rpm 6 5 8 7 Plastic 70 56 71 56 Viscosity, cP Yield Pt, 39 32 42 32 lb/100 ft{circumflex over ( )}2 Gels, 10 6/6 5/5 8/8 7/9 sec/10 min. API filt, 3.5 6.2 ml total API filt, — — ml oil API filt, 3.5 6.2 ml emulsion API filt, — — ml brine HTHP at 19.4 (0.8 150° F., ml brine) HTHP at 250° F., ml 250° F. oil 250° F. emulsion 250° F. brine Comments

[0049] Cesium formate, IA - 35 (50/50 mixture) 175 ml IA - 35 (0.828 sg) - (144.9 grams) 175 ml Cesium Formate (2.2 sg) - (385 grams) Mixing Procedure: 1. Measure out IA - 35 1A. Add Synvis, mix 5 minutes 2. Add CsF, mix 10 min. 3. Add Synvert 5, mix 10 minutes 3A. Add calcium carbonate, mix 10 minutes 4. Run initial ES, viscosities at 120° F. 5. Put 10 ml sample in a vial, SA for 24 hrs at 75° F., measure volumes 6. Hot-roll for 16 hours at 150° F. 7. Remix, run rheology, ES, API, HTHP at 150° F. 8. Put vials in oven and static-age at 150° F. for 24 hrs, measure volumes 9. If 150° F. HTHP is good, run at 250° F. 50/50 ratio Mud weight, 13.1 Lb/gal Sample # 313 314 314A 314B 315 316 317 318 IA - 35, grams 134.9 134.9 134.9 134.9 134.9 134.9 134.9 134.9 Cesium 385 385 385 385 385 385 385 385 Formate, grams Integrity 10 10 15 20 10 10 10 10 Emulsifier, lb/bbl Integrity 0.5 0.5 0.5 0.5 0.5 0.5 1 1 Synvis, lb/bbl Witco DTA 1 1.25 1.125 1.125 1.5 1.75 1 1.25 350, lb/bbl Baroid 50 50 50 50 50 50 50 50 Baracarb 50, lb/bbl Initial 330 332 353 355 437 402 298 330 ES, volts Hot-rolled 416 343 284 290 396 427 344 396 16 hrs, ES Initial Properties 600 rpm at 89 102 70 72 108 120 91 104 120° F. 300 rpm 58 66 40 39 78 83 59 70 200 rpm 47 53 30 28 66 70 48 57 100 rpm 35 42 19 16 53 56 36 44   6 rpm 20 26 4 2 32 31 20 25   3 rpm 17 21 3 1 26 19 18 22 Plastic 31 36 30 33 30 37 32 34 Viscosity, cP Yield Pt, 27 30 10 6 48 46 27 36 lb/100 ft{circumflex over ( )}2 Gels, 10 23/19 25/25 4/9 2/3 19/25 19/19 17/23 23/27 sec/10 min. Settling in No No No No No No No No thermocup HR 16 hrs at 150° F. 600 rpm at 93 93 82 73 93 95 113 124 120° F. 300 rpm 67 67 54 40 67 69 81 93 200 rpm 57 57 44 29 58 60 69 81 100 rpm 46 47 34 17 48 49 55 67   6 rpm 23 25 14 3 28 27 22 32   3 rpm 17 19 10 2 20 19 18 24 Plastic 26 26 28 33 26 26 32 31 Viscosity, cP Yield Pt, 41 41 26 7 41 43 49 62 lb/100 ft{circumflex over ( )}2 Gels, 10 19/23 21/21 12/15 3/4 23/23 21/19 21/26 26/21 sec/10 min. API filt, 1.2 1.8 5.8 2.6 2.2 1.2 0.2 3 ml total API filt, 0.8 1 0.7 0.6 1 0.2 0.1 0.9 ml oil API filt, 0.4 0.8 5.1 2.0 1.2 1 0.1 2.1 ml emulsion API filt, 0 0 0 0 0 0 0 0 ml brine HTHP at 150° F., ml HTHP at 250° F., ml Comments oil on oil on oil on top top top of jar of jar of jar 24 hrs at 75° F. Total fluid 38 38 38 38 38 38 heighth free oil 0.1 1.0 0.1 0.1 0.1 0.1 heighth emusion 38 37 38 38 38 38 heighth free brine 0 0 0 0 0 0 heighth free oil, % 0.3% 2.6% 0.3% 0.3% 0.3% 0.3% emusion, % 100.0% 97.4% 100.0% 100.0% 100.0% 100.0% free brine, % 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 24 hrs at 150° F. Total fluid 38 38 38 38 38 38 heighth free oil 4 4 3 3 2 2 heighth emusion 34 34 35 35 36 36 heighth free brine 0 0 0 0 0 0 heighth free oil, % 10.5% 10.5% 7.9% 7.9% 5.3% 5.3% emusion, % 89.5% 89.5% 92.1% 92.1% 94.7% 94.7% free brine, % 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 72 hrs at 150° F. Total fluid heighth free oil heighth emusion heighth free brine heighth free oil, % emusion, % free brine, % 50/50 ratio Mud weight, 13.1 Lb/gal Sample # 319 320 321 322 323 324 IA - 35, grams 134.9 134.9 134.9 134.9 134.9 134.9 Cesium 385 385 385 385 385 385 Formate, grams Integrity 10 10 10 10 10 10 Emulsifier, lb/bbl Integrity 1 1 1.5 1.5 1.5 1.5 Synvis, lb/bbl Witco DTA 1.5 1.75 1 1.25 1.5 1.75 350, lb/bbl Baroid 50 50 50 50 50 50 Baracarb 50, lb/bbl Initial 309 377 245 282 263 358 ES, volts Hot-rolled 346 355 324 268 380 382 16 hrs, ES Initial Properties 600 rpm 115 111 91 117 127 136 at 120° F. 300 rpm 77 78 52 74 85 97 200 rpm 64 64 38 59 70 82 100 rpm 49 49 23 43 54 66   6 rpm 27 27 7 23 30 36   3 rpm 22 22 6 19 24 28 Plastic 38 33 39 43 42 39 Viscosity, cP Yield Pt, 39 45 13 31 43 58 lb/100 ft{circumflex over ( )}2 Gels, 10 24/24 23/26 7/12 21/26 26/29 29/29 sec/10 min. Settling No No No No No No in thermocup HR 16 hrs at 150° F. 600 rpm 122 118 133 140 147 148 at 120° F. 300 rpm 90 90 98 101 111 111 200 rpm 78 79 83 86 96 97 100 rpm 64 65 68 69 78 78   6 rpm 32 32 28 31 34 34   3 rpm 23 23 22 23 25 25 Plastic 32 28 35 39 36 37 Viscosity, cP Yield Pt, 58 62 63 62 75 74 lb/100 ft{circumflex over ( )}2 Gels, 10 24/19 21/18 25/31 27/258 26/26 28/26 sec/10 min. API filt, 2 1.5 2.3 2.4 1.0 0.8 ml total API filt, 1 1 0.5 0.8 0.3 0.6 ml oil API filt, 1 0.5 1.8 1.6 0.7 0.2 ml emulsion API filt, 0 0 0 0 0 0 ml brine HTHP at 150° F., ml HTHP at 250° F., ml Comments oil on oil on top top of jar of jar 24 hrs at 75° F. Total fluid 38 38 38 38 38 38 heighth free oil 0.1 0.1 1.0 0.1 0.1 0.1 heighth emusion 38 38 37 38 38 38 heighth free brine 0 0 0 0 0 0 heighth free oil, % 0.3% 0.3% 2.6% 0.3% 0.3% 0.3% emusion, % 100.0% 100.0% 97.4% 100.0% 100.0% 100.0% free brine, % 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 24 hrs at 150° F. Total fluid 38 38 38 38 38 38 heighth free oil 3 2 4 3 2 2 heighth emusion 35 36 34 35 36 36 heighth free brine 0 0 0 0 0 0 heighth free oil, % 7.9% 5.3% 10.5% 7.9% 5.3% 5.3% emusion, % 92.1% 94.7% 89.5% 92.1% 94.7% 94.7% free brine, % 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

[0050] Cesium formate, IA - 35 (50/50 mixture) 175 ml IA - 35 (0.828 sg) - (144.9 grams) 175 ml Cesium Formate (2.2 sg) - (385 grams) Mixing Procedure: 529.9 350 2.2 sg 331.4 csf 1. Measure out IA - 35 559.24 8 50 18.52 13.1080 1A. Add Synvis, mix 5 minutes 50 18.52 2 2. Add CsF, mix 10 min. 609.24 350 1.740686 22.5 3. Add Synvert 5, mix 10 minutes 1.6871 2.70108 0.373 3A. Add calcium carbonate, mix 10 minutes 0.828 5 0.309258 0.626 4. Run initial ES, viscosities at 120° F. 2.2 5 1.3783 5. Put 10 ml sample in a vial, SA 1.687558 for 24 hrs at 75° F., measure volumes 559.2 6. Hot-roll for 16 hours at 150° F. 2.3 sg 4 331.48 csf 7. Remix, run rheology, ES, API, HTHP at 150° F. 50 18.52 609.2 14.4999 8. Put vials in oven and static-age at 150° F. 4 350 1.740686 1 for 24 hrs, measure volumes 1.687 1 9. If 150° F. HTHP is good, run at 250° F. 0.828 0.4163 0.344696 2.3 0.5837 1.34251 1.687206 Additional 0.5 lb/bbl 137.995 1 114.26 193.484 445.015 9 2 37/63 Oil/Formate ratio 14.4 lb/gal Sample # H.R. 16 hrs at 250° F. 325 326 327 328 329 329 329 330 IA - 35, grams 87.5 87.5 87.5 87.5 87.5 87.5 87.5 87.5 Cesium 456.9 456.9 456.9 456.9 456.9 456.9 456.9 456.9 Formate, grams Integrity 15 15 15 15 15 15 15 15 Emulsifier, lb/bbl Integrity — 1 2 2 1 1 1 — Synvis, lb/bbl Witco DTA — 1 1 2 — — — 1 350, lb/bbl Baroid 50 50 50 50 50 50 50 50 Baracarb 50, lb/bbl Initial 167 395 413 443 303 303 378 ES, volts Hot-rolled 221 372 377 488 284 284 259 324 16 hrs, ES Initial Properties 120° F. 600 rpm 163 233 300+  300+  251 247 177 at 120° F. 300 rpm 97 142 210 300+  154 156 106 200 rpm 71 107 162 253 116 121 78 100 rpm 42 64 104 185 71 71 46   6 rpm 6 9 22 66 11 13 5   3 rpm 4 6 16 53 8 10 3 Plastic 66 91 — — 97 91 71 Viscosity, cP Yield Pt, 31 51 — — 57 65 35 lb/100 ft{circumflex over ( )}2 Gels, 10 4/5 6/7 15/18 53/81 7/9 10/18 3/4 sec/10 min. Settling in slight thermocup sag HR 16 hrs at 150° F. 150° F. 150° F. 600 rpm 177 267 300+  300+  273 179 165 200 at 120° F. 300 rpm 108 177 260 300+  180 114 101 128 200 rpm 80 137 208 300+  140 87 76 99 100 rpm 48 92 140 252 91 54 46 65   6 rpm 8 21 40 98 20 10 8 15   3 rpm 5 16 32 80 15 7 6 11 Plastic 69 90 — — 93 65 64 72 Viscosity, cP Yield Pt, 39 87 — — 87 49 37 56 lb/100 ft{circumflex over ( )}2 Gels, 10 5/6 15/33 30/57 80/114 14/17 7/8 6/6 10/11 sec/10 min. API filt, 0.7 0.8 0 0 0 9 ml total API filt, 0 0 0 0 0 0 ml oil API filt, 0.7 0.8 0 0 0 9 ml emulsion API filt, ml brine HTHP at 150° F., ml HTHP at 12.6 7.2 250° F., ml 250° F. oil 0 0 250° F. 11.8 6.4 emulsion 250° F. 0.8 0.8 brine Comments 24 hrs at 75° F. Total fluid 39 38 38 38 38 38 heighth free oil 1.0 0.0 0.0 0.0 0.0 0.0 heighth emusion 38 38 38 38 38 38 heighth free brine 0 0 0 0 0 0 heighth free oil, % emusion, % free brine, % 24 hrs at 150° F. Total fluid heighth free oil heighth emusion heighth free brine heighth free oil, % emusion, % free brine, % 72 hrs at 150° F. Total fluid heighth free oil heighth emusion heighth free brine heighth free oil, % emusion, % free brine, % 37/63 Oil/Formate ratio 14.4 lb/gal Sample # Hot roll 16 hrs at 250° F. 331 332 332 332 333 334 IA - 35, grams 82.5 82.5 82.5 82.5 82.5 82.5 Cesium 456.9 456.9 456.9 456.9 456.9 456.9 Formate, grams Integrity 20 20 20 20 20 20 Emulsifier, lb/bbl Integrity — 1 1 1 — 0.5 Synvis, lb/bbl Witco DTA 1 — — — — — 350, lb/bbl Baroid 50 50 50 50 50 50 Baracarb 50, lb/bbl Initial 427 285 285 351 337 310 277 ES, volts Hot-rolled 391 363 363 293 16 hrs, ES Initial Properties 120° F. 120° F. 150° F. 120° F. 150° F. 600 rpm 223 247 273 218 170 230 170 at 120° F. 300 rpm 137 152 172 132 103 139 103 200 rpm 104 14 131 98 76 104 76 100 rpm 63 69 83 59 46 62 46   6 rpm 9 12 15 8 8 9 8   3 rpm 5 8 11 6 5 6 5 Plastic 86 95 101 86 67 91 67 Viscosity, cP Yield Pt, 51 57 71 46 36 48 36 lb/100 ft{circumflex over ( )}2 Gels, 10 5/6 8/9 12/15 6/7 6/6 6/7 6/6 sec/10 min. Settling in thermocup HR 16 hrs at 150° F. 150° F. 120° F. 120° F. 150° F. 120° F. 150° F. 600 rpm 223 280 186 174 222 179 245 176 at 120° F. 300 rpm 140 179 117 103 139 112 155 111 200 rpm 106 138 89 76 106 86 119 83 100 rpm 66 89 55 45 67 54 76 52   6 rpm 11 19 11 8 13 11 15 10   3 rpm 7 14 8 6 9 8 10 7 Plastic 83 101 69 71 83 67 90 65 Viscosity, cP Yield Pt, 57 78 48 32 56 45 65 46 lb/100 ft{circumflex over ( )}2 Gels, 10 7/8 14/18 8/9 6/7 9/10 8/9 10/15 7/8 sec/10 min. API filt, 3.5 0 1.1 0.3 ml total API filt, 0 0 0.0 0.0 ml oil API filt, 3.5 0 1.1 0.3 ml emulsion API filt, ml brine HTHP at 150° F., ml HTHP at 11.4 9.6 40.0 23.2 250° F., ml 250° F. oil 0 0 0.0 0.0 250° F. 11.4 8.6 36.0 21.2 emulsion 250° F. 0.6 1.0 4.0 2.0 brine Comments 24 hrs at 75° F. Total fluid 38 38 heighth free oil 0.0 0.0 heighth emusion 38 38 heighth free brine 0 0 heighth 37/63 Oil/Formate ratio 14.4 lb/gal Sample # Synvis added after h.r. 335 336 334A 336A IA - 35, grams 82.5 82.5 82.5 82.5 Cesium 456.9 456.9 456.9 456.9 Formate, grams Integrity 25 25 20 25 Emulsifier, lb/bbl Integrity — 0.5 1.0 1.0 Synvis, lb/bbl Witco DTA — — — — 350, lb/bbl Baroid 50 50 50 50 Baracarb 50, lb/bbl Initial 400 278 337 344 405 297 381 312 ES, volts Hot-rolled 297 313 312 353 16 hrs, ES Initial Properties 120° F. 150° F. 120° F. 150° F. 120° F. 150° F. 120° F. 150° F. 600 rpm at 120° F. 245 192 264 206 300+  219 300+  227 300 rpm 151 119 162 127 194 135 197 141 200 rpm 114 90 122 96 151 102 150 108 100 rpm 70 56 75 59 96 63 94 68   6 rpm 12 10 14 12 18 12 18 14   3 rpm 8 7 10 9 13 8 13 11 Plastic 94 73 102 79 — 84 — 86 Viscosity, cP Yield Pt, 57 46 60 48 — 51 — 55 lb/100 ft{circumflex over ( )}2 Gels, 10 8/9 8/9 10/11 9/10 12/16 8/9 13/17 11/11 sec/10 min. Settling in thermocup HR 16 hrs at 150° F. 600 rpm 241 192 264 210 300+  200 297 220 at 120° F. 300 rpm 152 123 169 133 200 127 191 141 200 rpm 116 94 129 103 157 97 148 109 100 rpm 73 60 83 66 104 62 97 70   6 rpm 15 14 18 15 25 13 22 16   3 rpm 11 10 13 11 20 10 17 12 Plastic 89 69 95 77 — 73 106 79 Viscosity, cP Yield Pt, 63 54 74 56 — 54 85 62 lb/100 ft{circumflex over ( )}2 Gels, 10 11/12 10/11 13/20 11/12 18/24 10/11 16/22 12/13 sec/10 min. API filt, 1.4 0.2 — 0.2 ml total API filt, 0.0 0.0 — 0.0 ml oil API filt, 1.4 0.2 — 0.2 ml emulsion API filt, ml brine HTHP at 150° F., ml HTHP at 45.6 27.6 12.0 12.0 250° F., ml 250° F. oil 0.0 0.0 0.0 0.0 250° F. 35.6 27.0 10.0 11.0 emulsion 250° F. 10.0 0.6 2.0 1.0 brine Comments 37/63 Oil/Formate ratio 14.4 lb/gal Sample # 0.5 lb/bbl Synvis added after h.r. 333 334 334A 335 IA - 35, grams 82.5 82.5 82.5 82.5 Cesium 456.9 456.9 456.9 456.9 Formate, grams Integrity 20 20 20 25 Emulsifier, lb/bbl Integrity — 0.5 1.0 — Synvis, lb/bbl Witco DTA — — — — 350, lb/bbl Baroid 50 50 50 50 Baracarb 50, lb/bbl Initial 351 337 310 277 405 297 400 278 ES, volts Hot-rolled 297 313 16 hrs, ES Initial Properties 120° F. 150° F. 120° F. 150° F. 120° F. 150° F. 120° F. 150° F. 600 rpm at 120° F. 218 170 230 170 300+  219 245 192 300 rpm 132 103 139 103 194 135 151 119 200 rpm 98 76 104 76 151 102 114 90 100 rpm 59 46 62 46 96 63 70 56   6 rpm 8 8 9 8 18 12 12 10   3 rpm 6 5 6 5 13 8 8 7 Plastic 86 67 91 67 — 84 94 73 Viscosity, cP Yield Pt, 46 36 48 36 — 51 57 46 lb/100 ft{circumflex over ( )}2 Gels, 10 6/7 6/6 6/7 6/6 12/16 8/9 8/9 8/9 sec/10 min. Settling in thermocup HR 16 hrs at 150° F. 600 rpm 222 179 245 176 300+  200 241 192 at 120° F. 300 rpm 139 112 155 111 200 127 152 123 200 rpm 106 86 119 83 157 97 116 94 100 rpm 67 54 76 52 104 62 73 60   6 rpm 13 11 15 10 25 13 15 14   3 rpm 9 8 10 7 20 10 11 10 Plastic 83 67 90 65 — 73 89 69 Viscosity, cP Yield Pt, 56 45 65 46 — 54 63 54 lb/100 ft{circumflex over ( )}2 Gels, 10 9/10 8/9 10/15 7/8 18/24 10/11 11/12 10/11 sec/10 min. API filt, 1.1 0.3 — 1.4 ml total API filt, 0.0 0.0 — 0.0 ml oil API filt, 1.1 0.3 — 1.4 ml emulsion API filt, ml brine HTHP at 150° F., ml HTHP at 40.0 23.2 12.0 45.6 250° F., ml 250° F. oil 0.0 0.0 0.0 0.0 250° F. 36.0 21.2 10.0 35.6 emulsion 250° F. 4.0 2.0 2.0 10.0 brine 37/63 Oil/Formate ratio 14.4 lb/gal Sample # 0.5 lb/bbl Synvis added after h.r. 336 336A IA - 35, grams 82.5 82.5 Cesium 456.9 456.9 Formate, grams Integrity 25 25 Emulsifier, lb/bbl Integrity 0.5 1.0 Synvis, lb/bbl Witco DTA — — 350, lb/bbl Baroid 50 50 Baracarb 50, lb/bbl Initial 337 344 381 312 ES, volts Hot-rolled 312 353 16 hrs, ES Initial Properties 120° F. 150° F. 120° F. 150° F. 600 rpm at 120° F. 264 206 300+  227 300 rpm 162 127 197 141 200 rpm 122 96 150 108 100 rpm 75 59 94 68   6 rpm 14 12 18 14   3 rpm 10 9 13 11 Plastic 102 79 — 86 Viscosity, cP Yield Pt, 60 48 — 55 lb/100 ft{circumflex over ( )}2 Gels, 10 10/11 9/10 13/17 11/11 sec/10 min. Settling in thermocup HR 16 hrs at 150° F. 600 rpm 264 210 297 220 at 120° F. 300 rpm 169 133 191 141 200 rpm 129 103 148 109 100 rpm 83 66 97 70   6 rpm 18 15 22 16   3 rpm 13 11 17 12 Plastic 95 77 106 79 Viscosity, cP Yield Pt, 74 56 85 62 lb/100 ft{circumflex over ( )}2 Gels, 10 13/20 11/12 16/22 12/13 sec/10 min. API filt, 0.2 0.2 ml total API filt, 0.0 0.0 ml oil API filt, 0.2 0.2 ml emulsion API filt, ml brine HTHP at 150° F., ml HTHP at 27.6 12.0 250° F., ml 250° F. oil 0.0 0.0 250° F. 27.0 11.0 emulsion 250° F. 0.6 1.0 brine Comments

[0051] Cesium formate, Escaid 110 (50/50 mixture) 175 ml Escaid 110 (0.803 sg) - (140.5 grams) 175 ml Cesium Formate (2.2 sg) - (385 grams) Mixing Procedure: 1. Measure out Escaid 110 2. Add emulsifiers, mix 5 minutes 3. Add CsF, mix 10 min. on HB, mix on Silverson to 135° F. 3A. Add Lo-Wate, mix 10 min. on HB 4. Run initial ES, viscosities at 120° F. 5. Put 10 ml sample in a vial, SA for 24 hrs at 75° F., measure volumes 6. Hot-roll for 16 hours at 150° F. 7. Remix, run rheology, ES, API, HTHP at 150° F. 8. Put vials in oven and static-age at 150° F. for 24 hrs, measure volumes 9. If 150° F. HTHP is good, run at 250° F. Sample # 273 274 275 276 277 278 Integrity Synvert 5 10 10 10 15 15 IV (Lot# 000329), lb/bbl Witco AX-180-2, 5 5 5 5 5 5 lb/bbl Witco DTA 2 3 2 350, lb/bbl dimer trimer Baroid 50 50 50 50 50 50 Baracarb 50, lb/bbl Initial 363 360 425 572 454 417 ES, volts @ 120° F. Hot-rolled 16 hrs. ES 399 410 378 489 403 329 Jar − S = Settling, S 3 S 3 S S 3 S S 3 = 3 Phases, N = No Initial Properties 600 rpm at 120° F. 24 25 29 42 27 29 300 rpm 13 14 17 30 15 15 200 rpm 9 9 12 25 10 11 100 rpm 5 5 8 19 6 6   6 rpm 1 1 2 10 2 1   3 rpm 1 1 1 7 1 1 Plastic 11 11 12 12 12 14 Viscosity, cP Yield Pt,lb/100 ft{circumflex over ( )}2 2 3 5 18 3 1 Gels, 10 1/1 1/1 2/2 7/8 1/2 1/1 sec/10 min. Settling in Y Y Y N Y Y thermocup HR 64 hrs at 150° F. 600 rpm at 120° F. 24 26 31 54 28 28 300 rpm 12 13 18 40 15 15 200 rpm 8 9 14 34 11 11 100 rpm 5 5 9 28 7 6   6 rpm 1 1 3 19 2 1   3 rpm 1 1 2 11 2 1 Plastic 12 13 13 14 13 13 Viscosity, cP Yield Pt, 0 0 5 26 2 2 lb/100 ft{circumflex over ( )}2 Gels, 10 1/1 1/1 2/2 14/8 2/2 1/1 sec/10 min. Settling in Y Y N N Y Y Thermocup Settling in Jar ¼″ ⅛″ {fraction (1/16)}″ — {fraction (1/16)}″ ⅛″ API filt, 3.2 1.8 2.0 2.0 1.4 2.6 ml total API filt, 1.6 1.6 2.0 2.0 0.4 2.6 ml oil API filt, 1.6 0.2 0.0 0.0 1.0 0.0 ml brine HTHP at 150° F., ml 8.6 6.6 8.6 8.0 9.8 13.4 HTHP at 250° F., ml 17.2 29.0 Static Age - 64 hrs at 75° F. Total fluid height 32 32 32 32 32 32 free oil height 4 3 7 7 2 3 emusion height 28 29 25 25 30 29 free brine height 0 0 0 0 0 0 free oil, % 13%   9% 22%  22%   6%   9% emusion, % 87.5% 90.6% 78.1% 78.1% 93.8% 90.6% free brine, % 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% Total 100%   100%   100%   100%   100%   100%   MP = Multiple MP MP MP MP MP MP Phase Emulsion Static Age - 24 hrs at 150° F. Total fluid height 32 32 32 32 32 32 free oil height 7 7 10 8 10 9 emusion height 25 25 22 24 22 23 free brine height 0 0 0 0 0 0 free oil, % 22%  22%  31%  25%  31%  28%  emusion, % 78.1% 78.1% 68.8% 75.0% 68.8% 71.9% free brine, % 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% Total 100%   100%   100%   100%   100%   100%   MP = Multiple MP MP MP MP MP MP Phase Emulsion Difference (64 hrs/24 hrs at 150° F.) free oil, % emusion, % free brine, % Sample # 279 280 281 282 283 284 Integrity Synvert IV 5 5 5 5 2.5 2.5 (Lot# 000329), lb/bbl Witco AX-180-2, lb/bbl 7.5 10 10 10 10 10 Witco DTA 2 3 2 350, lb/bbl dimer trimer Baroid 50 50 50 50 50 50 Baracarb 50, lb/bbl Initial 448 390 445 552 360 458 ES, volts @ 120° F. Hot-rolled 398 431 345 288 359 229 16 hrs, ES Jar − S = Settling, S S N N S S 3 = 3 Phases, N = No Initial Properties 600 rpm at 120° F. 26 24 30 47 24 32 300 rpm 14 13 18 33 13 19 200 rpm 9 9 13 28 9 15 100 rpm 5 5 9 21 5 10   6 rpm 1 1 3 9 2 3   3 rpm 1 1 3 6 1 2 Plastic 12 11 12 14 11 13 Viscosity, cP Yield Pt, 2 2 6 19 2 6 lb/100 ft{circumflex over ( )}2 Gels, 10 1/2 1/2 3/4 6/6 1/2 3/3 sec/10 min. Settling in Y Y Y N Y N thermocup HR 64 hrs at 150° F. 600 rpm at 120° F. 25 25 32 56 25 35 300 rpm 13 13 20 42 13 22 200 rpm 9 9 16 36 9 13 100 rpm 5 5 11 28 5 12   6 rpm 1 1 4 15 1 4   3 rpm 1 1 3 8 1 4 Plastic 12 12 12 14 12 13 Viscosity, cP Yield Pt, 1 1 8 28 1 9 lb/100 ft{circumflex over ( )}2 Gels, 10 1/1 1/1 4/5 7/5 2/2 5/3 sec/10 min. Settling in Y Y Y N Y N Thermocup Settling in Jar ¼″ ¼″ — ¼″ {fraction (5/16)}″ — API filt, 3.0 3.2 2.0 2.1 2.1 2.2 ml total API filt, 0.8 1.2 1.8 1.8 1.4 1.9 ml oil API filt, 2.2 2.0 0.2 0.2 0.7 0.3 ml brine HTHP at 150° F., ml 11.6 14.6 7.0 4.4 12.0 5.6 HTHP at 250° F., ml 15.0 12.4 20.8 14.8 Static Age - 64 hrs at 75° F. Total fluid height 32 32 32 32 32 32 free oil height 3 8 9 10 9 9 emusion height 29 24 23 22 23 23 free brine height 0 0 0 0 0 0 free oil, %  9% 25%  28%  31%  28%  28%  emusion, % 90.6% 75.0% 71.9% 68.8% 71.9% 71.9% free brine, % 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% Total 100%   100%   100%   100%   100%   100%   MP = Multiple MP — — — — — Phase Emulsion Static Age - 24 hrs at 150° F. Total fluid height 32 32 32 32 32 32 free oil height 4 10 10 10 10 10 emusion height 28 22 22 22 22 22 free brine height 0 0 0 0 0 0 free oil, % 13%  31%  31%  31%  31%  31%  emusion, % 87.5% 68.8% 68.8% 68.8% 68.8% 68.8% free brine, % 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% Total 100%   100%   100%   100%   100%   100%   MP = Multiple MP — — — — — Phase Emulsion Difference (64 hrs/24 hrs at 150° F.) free oil, % emusion, % free brine, %

[0052] Cesium formate, IA - 35 (50/50 mixture) 175 ml IA - 35 (0.828 sg) - (144.9 grams) NOTE: Make up ½ bbl 175 ml Cesium Formate (2.2 sg) - (385 grams) Equivalents Mixing Procedure: 1. Measure out IA - 35 1A. Add Synvis, mix 5 minutes 2. Add CsF, mix 10 min. 3. Add Synvert 5, mix 10 minutes 3A. Add calcium carbonate, mix 10 minutes 4. Run initial ES, viscosities at 120° F. 5. Put 10 ml sample in a vial, SA for 24 hrs at 75° F., measure volumes 6. Hot-roll for 16 hours at 150° F. NOTE: Make up ½ bbl Equivalents 7. Remix, run rheology, ES, API, HTHP at 150° F. 8. Put vials in oven and static-age at 150° F. for 24 hrs, measure volumes 9. If 150° F. HTHP is good, run at 250° F. NOTE: Make up ½ bbl Equivalents oil/cs ratio 50/50 50/50 50/50 50/50 53/47 Sample # 285 285 286 287 287 288 289 IA - 35, grams 119.9 119.9 119.9 119.9 119.9 119.9 144.9 Cesium 385 385 385 385 385 385 385 Formate, grams Integrity Synvert 25 25 25 25 25 25 25 5, lb/bbl Integrity 5 5 5 10 10 10 5 Synvis, lb/bbl Baroid — — 50 — — 50 — Baracarb 50, lb/bbl Initial 823 680 646 595 641 ES, volts Hot-rolled 494 619 551 528 509 16 hrs, ES Initial Properties 600 rpm at 273 164 300+  300+  300+  300+  142 120° F. 300 rpm 184 94 230 300+  290 300+  85 200 rpm 144 67 182 300+  230 300+  64 100 rpm 102 39 130 229 157 300+  40   6 rpm 39 7 41 81 45 119 10   3 rpm 26 5 37 72 38 105 8 Plastic 89 70 — — — 57 Viscosity, cP Yield Pt, 95 24 — — — 28 lb/100 ft{circumflex over ( )}2 Gels, 10 23/27 5/7 33/37 65/72 35/42 87/96 7/9 sec/10 min. Settling in N N N N N thermocup API filt, 10 (8 min) 0 1.5 0 10 (2 min) ml total API filt, 0 0 0 0 0 ml oil API filt, 0 0 0 0 0 ml brine HTHP at 150° F., ml HTHP at 250° F., ml HR 16 hrs at 150° F. 600 rpm at 120° F. 270 294 300+  300+  197 300 rpm 171 184 300+  300+  120 200 rpm 132 148 300+  300+  90 100 rpm 89 100 300+  284 60   6 rpm 24 28 102 95 16   3 rpm 19 23 87 83 13 Plastic 99 110 — — 77 Viscosity, cP Yield Pt, 72 74 — — 43 lb/100 ft{circumflex over ( )}2 Gels, 10 16/21 21/25 81/86 74/84 11/16 sec/10 min. Comments 24 hrs at 75° F. Total fluid 33 34 34 33 34 heighth free oil 0 0 0 0 0 heighth emusion 33 34 34 33 34 heighth free brine 0 0 0 0 0 heighth free oil, %  0%  0%  0%  0%  0% emusion, % 100.0% 100.0% 100.0% 100.0% 100.0% free brine, % 0.0% 0.0% 0.0% 0.0% 0.0% 24 hrs at 150° F. Total fluid 33 34 34 33 34 heighth free oil 0 0 0 0 0 heighth emusion 33 34 34 33 34 heighth free brine 0 0 0 0 0 heighth free oil, %  0%  0%  0%  0%  0% emusion, % 100.0% 100.0% 100.0% 100.0% 100.0% free brine, % 0.0% 0.0% 0.0% 0.0% 0.0% 72 hrs at 150° F. Total fluid 33 34 34 33 34 heighth free oil 1 2 0 0 2 heighth emusion 32 32 34 33 32 heighth free brine 0 0 0 0 0 heighth free oil, %  3%  6%  0%  0%  6% emusion, % 97.0% 94.1% 100.0% 100.0% 94.1% free brine, % 0.0% 0.0% 0.0% 0.0% 0.0% API filt, ml total API filt, ml oil API filt, ml brine HTHP at 150° F., ml HTHP at 250° F., ml HR 16 hrs at 150° F. 600 rpm at 120° F. 292 200 300 rpm 192 124 200 rpm 151 94 100 rpm 102 59   6 rpm 31 14   3 rpm 25 11 Plastic 100 76 Viscosity, cP Yield Pt, 92 48 lb/100 ft{circumflex over ( )}2 Gels, 10 23/26 10/12 sec/10 min. Comments oil/cs ratio 53/47 48.5/51.5 48.5/51.5 48.5/51.5 48.5/51.5 56/44 56/44 Sample # 290 291 292 293 294 295 296 IA - 35, grams 144.9 94.9 94.9 94.9 94.9 144.9 144.9 Cesium 385 385 385 385 385 385 385 Formate, grams Integrity Synvert 25 50 50 50 50 50 50 5, lb/bbl Integrity 10 5 5 10 10 5 10 Synvis, lb/bbl Baroid — — 50 — 50 — — Baracarb 50, lb/bbl Initial 1032 452 392 409 337 651 698 ES, volts Hot-rolled 660 469 442 373 341 490 645 16 hrs, ES Initial Properties 600 rpm at 120° F. 300+  262 300+  300+  300+  114 300+  300 rpm 300+  164 193 300+  300+  68 230 200 rpm 287 129 149 300+  300+  50 184 100 rpm 243 86 100 300+  221 33 126   6 rpm 83 24 28 115 73 11 38   3 rpm 73 19 22 98 61 9 31 Plastic — 98 — — — 46 — Viscosity, cP Yield Pt, — 66 — — — 22 — lb/100 ft{circumflex over ( )}2 Gels, 10 64/69 19/25 21/28 89/103 57/76 4/4 29/36 sec/10 min. Settling in N N N N N N N thermocup API filt, 1.5 10 (2 0.0 7.0 0.0 6.9 10 (2 ml total min) min) API filt, 0 0 0 0 0 0 0 ml oil API filt, 0 0 0 0 0 0 0 ml brine HTHP at 150° F., ml HTHP at 250° F., ml HR 16 hrs at 150° F. 600 rpm at 120° F. 300+  300+  300+  300+  300+  152 300+  300 rpm 300+  206 257 300+  300+  89 203 200 rpm 243 160 202 300+  300+  65 155 100 rpm 177 109 140 263 298 41 106   6 rpm 69 33 43 89 100 11 32   3 rpm 59 29 36 78 88 9 27 Plastic — — — — — 63 — Viscosity, cP Yield Pt, — — — — — 26 — lb/100 ft{circumflex over ( )}2 Gels, 10 46/53 24/33 33/42 70/80 78/88 3/4 25/32 sec/10 min. Comments 24 hrs at 75° F. Total fluid 34 35 34 33 33 34 34 heighth free oil 0 0 0 0 0 0 0 heighth emusion 34 35 34 33 33 34 34 heighth free brine 0 0 0 0 0 0 0 heighth free oil, %  0%  0%  0%  0%  0%  0%  0% emusion, % 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% free brine, % 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 24 hrs at 150° F. Total fluid 34 35 34 33 33 34 34 heighth free oil 0 0 1 0 0 1 0 heighth emusion 34 35 33 33 33 33 34 heighth free brine 0 0 0 0 0 0 0 heighth free oil, %  0%  0%  3%  0%  0%  3%  0% emusion, % 100.0% 100.0% 97.1% 100.0% 100.0% 97.1% 100.0% free brine, % 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 72 hrs at 150° F. Total fluid 34 35 34 33 33 34 34 heighth free oil 0 2 2 0 0 5 0 heighth emusion 34 33 32 33 33 29 34 heighth free brine 0 0 0 0 0 0 0 heighth free oil, %  0%  6%  6%  0%  0% 15%   0% emusion, % 100.0% 94.3% 94.1% 100.0% 100.0% 85.3% 100.0% free brine, % 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% HR 16 hrs at 150° F. 600 rpm at 300+  144 120° F. 300 rpm 240 83 200 rpm 189 61 100 rpm 129 38   6 rpm 41 9   3 rpm 34 7 Plastic 61 Viscosity, cP Yield Pt, — 22 lb/100 ft{circumflex over ( )}2 Gels, 10 32/38 7/9 sec/10 min. Comments

[0053] Cesium formate, Escaid 110 (50/50 mixture) 175 ml Escaid 110 (0.803 sg) - (140.5 grams) 175 ml Cesium Formate (2.2 sg) - (385 grams) Mixing Procedure: 1. Measure out Escaid 110 2. Add emulsifiers, mix 5 minutes, add Barablock, mix 10 minutes 3. Add CsF, mix 10 min. on HB, mix on Silverson to 135° F. 3A. Add Lo-Wate, mix 10 min. on HB 4. Run initial ES, viscosities at 120° F. 5. Put 10 ml sample in a vial, SA for 24 hrs at 75° F., measure volumes 6. Hot-roll for 16 hours all 50° F. 7. Remix, run rheology, ES, API, HTHP at 150° F. 8. Put vials in oven and static-age at 150° F. for 24 hrs, measure volumes 9. If 150° F. HTHP is good, run at 250° F. Sample # 261 262 262 264 265 266 Integrity 10 15 20 15 Synvert IV (Lot # 000329), lb/bbl Rhodia Miranol 7 10.5 CS, lb/bbl Witco AX-180-2, lb/bbl Witco DTA 3 350, lb/bbl dimer trimer Baroid 50 50 50 50 50 50 Baracarb 50, lb/bbl Initial 285 306 355 327 8 1 ES, volts Hot-rolled 320 350 314 376 2 1 16 hrs, ES Initial Properties 600 rpm at 120° F. 26 25 25 27 64 66 300 rpm 13 12 13 13 40 41 200 rpm 9 8 9 8 32 32 100 rpm 5 4 4 4 22 23   6 rpm 1 1 1 0 7 8   3 rpm 1 1 1 0 4 5 Plastic 13 13 12 14 24 25 Viscosity, cP Yield Pt,lb/100 ft{circumflex over ( )}2 0 −1 1 −1 16 16 Gels, 10 0/1 0/1 1/1 1/1 6/4 6/5 sec/10 min. Settling in yes yes yes yes no no thermocup API filt, 4.8 4.1 2.7 2.7 11 (1 min) 10 (1 min) ml total API filt, — — — — — — ml oil API filt, — — — — 4.2 7.0 ml brine HR 16 hrs at 150° F. 600 rpm at 120° F. 26 26 27 42 63 54 300 rpm 14 13 14 25 40 34 200 rpm 9 8 9 20 31 28 100 rpm 5 5 5 14 19 20   6 rpm 1 1 1 3 6 6   3 rpm 1 1 1 3 4 3 Plastic 12 13 13 17 23 20 Viscosity, cP Yield Pt, 2 0 1 8 17 14 lb/100 ft{circumflex over ( )}2 Gels, 10 1/1 1/1 1/1 1/1 4/5 5/4 sec/10 min. Comments settling settling settling ¼ 3 3 inch oil phases phases 24 hrs at 75° F. Total fluid 32 33 33 32 32 32 heighth free oil 2 2 2 2 0 0 heighth emusion 28 29 29 30 21 21 heighth free brine 0 0 0 0 11 11 heighth free oil, %  6%  6%  6%  6%  0%  0% emusion, % 87.5% 87.9% 87.9% 93.8% 65.6% 65.6% free brine, % 0.0% 0.0% 0.0% 0.0% 34.4% 34.4% 24 hrs at 150° F. Total fluid 32 33 33 32 32 32 heighth free oil 2 4 3 5 0 0 heighth emusion 30 29 30 27 21 20 heighth free brine 0 0 0 0 11 12 heighth free oil, %  6% 12%   9% 16%   0%  0% emusion, % 93.8% 87.9% 90.9% 84.4% 65.6% 62.5% free brine, % 0.0% 0.0% 0.0% 0.0% 34.4% 37.5% Difference (72 hrs/24 hrs at 150° F.) free oil, %  0%  6%  3%  9%  0%  0% emusion, %  6%  0%  3% −9%  0% −3% free brine, %  0%  0%  0%  0%  0%  3% Sample # 267 268 269 270 271 272 Integrity Synvert IV (Lot# 000329), lb/bbl Rhodia Miranol 14 10.5 CS, lb/bbl Witco AX-180-2, 7 10.5 14 10.5 lb/bbl Witco DTA 3 3 350, lb/bbl dimer trimer Baroid 50 50 50 50 50 50 Baracarb 50, lb/bbl Initial 1 37 151 318 349 345 ES, volts Hot-rolled 0 18 175 351 419 321 16 hrs, ES Initial Properties 600 rpm at 120° F. 66 67 30 24 25 94 300 rpm 42 47 17 13 13 70 200 rpm 34 50 13 9 9 59 100 rpm 24 31 8 6 6 46   6 rpm 8 2 2 1 1 15   3 rpm 4 2 2 1 1 6 Plastic 24 20 13 11 12 24 Viscosity, cP Yield Pt, 18 27 4 2 1 46 lb/100 ft{circumflex over ( )}2 Gels, 10 6/4 5/12 2/3 1/1 1/1 9/7 sec/10 min. Settling in no no no yes yes no thermocup API filt, 10 (1 min) 1.9 2.6 1/1 0.9 0.4 ml total API filt, — 0.6 — — — — ml oil API filt, 2.5 0.3 — — — — ml brine HR 16 hrs at 150° F. 600 rpm at 62 67 33 28 28 79 120° F. 300 rpm 39 42 19 16 16 61 200 rpm 32 37 15 12 11 53 100 rpm 22 26 10 8 7 42   6 rpm 7 2 3 2 2 16   3 rpm 4 2 2 2 2 7 Plastic 23 25 14 12 12 18 Viscosity, cP Yield Pt, 16 17 5 4 4 43 lb/100 ft{circumflex over ( )}2 Gels, 10 6/5 2/9 3/4 3/3 2/2 9/6 sec/10 min. Comments 3 phases 2 phases sagging sagging sagging ⅜ inch oil 24 hrs at 75° F. Total fluid 32 32 32 32 32 32 heighth free oil 0 12 4 4 4 5 heighth emusion 23 20 28 28 28 27 heighth free brine 9 0 0 0 0 0 heighth free oil, %  0% 38%  13%  13%  13%  16%  emusion, % 71.9% 62.5% 87.5% 87.5% 87.5% 84.4% free brine, % 28.1% 0.0% 0.0% 0.0% 0.0% 0.0% 24 hrs at 150° F. Total fluid 32 32 32 32 32 32 heighth free oil 0 12 7 5 5 12 heighth emusion 22 20 25 27 27 20 heighth free brine 10 0 0 0 0 0 heighth free oil, %  0% 38%  22%  16%  16%  38%  emusion, % 68.8% 62.5% 78.1% 84.4% 84.4% 62.5% free brine, % 31.3% 0.0% 0.0% 0.0% 0.0% 0.0% Difference (72 hrs/24 hrs at 150° F.) free oil, %  0%  0%  9%  3%  3% 22%  emusion, % −3%  0% −9% −3% −3% −22%  free brine, % 3%  0%  0%  0%  0%  0%

[0054] Other embodiments of the present invention will be apparent to those skilled in the art from consideration of the present specification and practice of the present invention disclosed herein. It is intended that the present specification and examples be considered as exemplary only with a true scope and spirit of the invention being indicated by the following claims and equivalents thereof. 

What is claimed is:
 1. A drilling fluid or mud comprising at least one alkali metal formate or monovalent carboxylic salt.
 2. A drilling fluid comprising at least one alkali metal formate and at least one emulsifier.
 3. The completion fluid of claim 2, further comprising at least one hydrocarbon-based fluid or synthetic mud fluid.
 4. The drilling fluid of claim 2, wherein said alkali metal formate comprises potassium formate.
 5. The drilling fluid of claim 2, wherein said drilling fluid further comprises at least one acid.
 6. The drilling fluid of claim 2, further comprising at least one solid weighting material, at least one fluid loss additive, at least one wetting agent, at least one organo clay, at least one filtration control agent, at least one polymer, or combinations thereof.
 7. The drilling fluid of claim 2, wherein said emulsifier comprises a dimer trimer acid, imidazoline, tall oil, or combinations thereof.
 8. The drilling fluid of claim 3, wherein said hydrocarbon-based fluid comprises diesel oil.
 9. The drilling fluid of claim 3, wherein said hydrocarbon-based fluid comprises at least one synthetic oil.
 10. The drilling fluid of claim 5, wherein said acid is formic acid or an acid derivative thereof.
 11. The drilling fluid of claim 1, wherein said alkali metal formate is less than fully saturated in said drilling fluid.
 12. A method to drill a well comprising drilling said well in the presence of the drilling fluid of claim
 1. 13. A method to drill a well comprising drilling said well in the presence of the drilling fluid of claim
 2. 14. A method to reduce the solids content in a drilling fluid comprising substituting at least a portion of said solid weighting material with an aqueous solution comprising at least one alkali metal formate.
 15. A drilling fluid or mud made by mixing at least one alkali metal formate and at least one emulsifier.
 16. A drilling fluid or mud made by mixing at least one alkali metal formate, at least one emulsifier, at least one hydrocarbon-based fluid or synthetic mud fluid. 